I've enabled log4j logging for alfresco-vti and this is what i am getting logged when trying to connect from MS Word:
12:04:35,760 DEBUG [org.alfresco.module.vti.VtiContextFilter] Checking request for VTI or not
12:04:35,761 DEBUG [org.alfresco.module.vti.VtiContextFilter] Target is not VTI request. Go to the next filter
12:04:35,853 DEBUG [org.alfresco.module.vti.VtiContextFilter] Checking request for VTI or not
12:04:35,853 DEBUG [org.alfresco.module.vti.VtiContextFilter] Target is not VTI request. Go to the next filter
12:04:35,857 DEBUG [org.alfresco.module.vti.VtiContextFilter] Checking request for VTI or not
12:04:35,857 DEBUG [org.alfresco.module.vti.VtiContextFilter] Target is not VTI request. Go to the next filter
12:04:41,648 DEBUG [org.alfresco.module.vti.VtiContextFilter] Checking request for VTI or not
12:04:41,648 DEBUG [org.alfresco.module.vti.VtiContextFilter] Target is VTI request
12:04:41,648 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Process request
12:04:41,649 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Find appropriate filters by pattern for uri='/alfresco/'
12:04:41,649 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Process filter
12:04:41,649 DEBUG [org.alfresco.module.vti.VtiFilter] Checking request for VTI or not
12:04:41,650 DEBUG [org.alfresco.module.vti.VtiFilter] Target is not VTI request
12:04:41,650 DEBUG [org.alfresco.module.vti.VtiFilter] Return VTI answer for OPTIONS request
12:04:41,650 DEBUG [org.alfresco.module.vti.VtiFilter] Check authentication
12:04:41,650 DEBUG [org.alfresco.module.vti.VtiFilter] Session user is null. Authenticate user.
12:04:41,650 DEBUG [org.alfresco.module.vti.VtiFilter] No user or ticket, force the client to prompt for logon details
12:05:08,699 DEBUG [org.alfresco.module.vti.VtiContextFilter] Checking request for VTI or not
12:05:08,699 DEBUG [org.alfresco.module.vti.VtiContextFilter] Target is VTI request
12:05:08,699 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Process request
12:05:08,699 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Find appropriate filters by pattern for uri='/alfresco/'
12:05:08,699 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Process filter
12:05:08,699 DEBUG [org.alfresco.module.vti.VtiFilter] Checking request for VTI or not
12:05:08,699 DEBUG [org.alfresco.module.vti.VtiFilter] Target is not VTI request
12:05:08,699 DEBUG [org.alfresco.module.vti.VtiFilter] Return VTI answer for OPTIONS request
12:05:08,699 DEBUG [org.alfresco.module.vti.VtiFilter] Check authentication
12:05:08,699 DEBUG [org.alfresco.module.vti.VtiFilter] Session user is null. Authenticate user.
12:05:08,700 DEBUG [org.alfresco.module.vti.VtiFilter] Authenticate the user 'sc'
12:05:08,802 DEBUG [org.alfresco.module.vti.VtiFilter] User was authenticated successfully
12:05:08,802 DEBUG [org.alfresco.module.vti.VtiFilter] Request accepted
12:05:08,802 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Find appropriate filters by pattern for uri='/alfresco/'
12:05:08,802 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Filter accept request for uri='/alfresco/'
12:05:08,802 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Find appropriate servlet by pattern for uri='/alfresco/'
12:05:08,913 DEBUG [org.alfresco.module.vti.VtiContextFilter] Checking request for VTI or not
12:05:08,913 DEBUG [org.alfresco.module.vti.VtiContextFilter] Target is VTI request
12:05:08,913 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Process request
12:05:08,913 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Find appropriate filters by pattern for uri='/alfresco/'
12:05:08,913 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Process filter
12:05:08,913 DEBUG [org.alfresco.module.vti.VtiFilter] Checking request for VTI or not
12:05:08,913 DEBUG [org.alfresco.module.vti.VtiFilter] Target is not VTI request
12:05:08,913 DEBUG [org.alfresco.module.vti.VtiFilter] Return VTI answer for HEAD request
12:05:08,913 DEBUG [org.alfresco.module.vti.VtiFilter] Checking is resource exist
12:05:08,917 ERROR [org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/alfresco].[jsp]] Servlet.service() for servlet jsp threw exception
org.alfresco.module.vti.VtiInternalErrorException: net.sf.acegisecurity.AuthenticationCredentialsNotFoundException: A valid SecureContext was not provided in the RequestContext
at org.alfresco.module.vti.handler.alfresco.AlfrescoVtiMethodHandlerThrowsAdvice.afterThrowing(AlfrescoVtiMethodHandlerThrowsAdvice.java:53)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.springframework.aop.framework.adapter.ThrowsAdviceInterceptor.invokeHandlerMethod(ThrowsAdviceInterceptor.java:146)
at org.springframework.aop.framework.adapter.ThrowsAdviceInterceptor.invoke(ThrowsAdviceInterceptor.java:131)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:166)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at $Proxy81.existResource(Unknown Source)
at org.alfresco.module.vti.VtiFilter.doFilter(VtiFilter.java:184)
at org.alfresco.module.vti.httpconnector.VtiServletContainer$HttpFilterChain.doFilter(VtiServletContainer.java:273)
at org.alfresco.module.vti.httpconnector.VtiServletContainer.service(VtiServletContainer.java:133)
at org.alfresco.module.vti.VtiContextFilter.doFilter(VtiContextFilter.java:101)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:210)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:174)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:870)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:685)
at java.lang.Thread.run(Thread.java:595)
Caused by: net.sf.acegisecurity.AuthenticationCredentialsNotFoundException: A valid SecureContext was not provided in the RequestContext
at net.sf.acegisecurity.intercept.AbstractSecurityInterceptor.credentialsNotFound(AbstractSecurityInterceptor.java:477)
at net.sf.acegisecurity.intercept.AbstractSecurityInterceptor.beforeInvocation(AbstractSecurityInterceptor.java:355)
at net.sf.acegisecurity.intercept.method.aopalliance.MethodSecurityInterceptor.invoke(MethodSecurityInterceptor.java:77)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:166)
at org.alfresco.repo.security.permissions.impl.ExceptionTranslatorMethodInterceptor.invoke(ExceptionTranslatorMethodInterceptor.java:49)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:166)
at org.alfresco.repo.audit.AuditComponentImpl.audit(AuditComponentImpl.java:275)
at org.alfresco.repo.audit.AuditMethodInterceptor.invoke(AuditMethodInterceptor.java:69)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:166)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:107)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:166)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at $Proxy44.resolveNamePath(Unknown Source)
at org.alfresco.module.vti.handler.alfresco.VtiPathHelper.resolvePathFileInfo(VtiPathHelper.java:136)
at org.alfresco.module.vti.handler.alfresco.AlfrescoVtiMethodHandler.existResource(AlfrescoVtiMethodHandler.java:946)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:296)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:177)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:144)
at org.springframework.aop.framework.adapter.ThrowsAdviceInterceptor.invoke(ThrowsAdviceInterceptor.java:126)
… 21 more
12:05:08,975 DEBUG [org.alfresco.module.vti.VtiContextFilter] Checking request for VTI or not
12:05:08,975 DEBUG [org.alfresco.module.vti.VtiContextFilter] Target is VTI request
12:05:08,975 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Process request
12:05:08,975 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Find appropriate filters by pattern for uri='/alfresco/'
12:05:08,975 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Process filter
12:05:08,975 DEBUG [org.alfresco.module.vti.VtiFilter] Checking request for VTI or not
12:05:08,975 DEBUG [org.alfresco.module.vti.VtiFilter] Target is not VTI request
12:05:08,975 DEBUG [org.alfresco.module.vti.VtiFilter] Return VTI answer for HEAD request
12:05:08,975 DEBUG [org.alfresco.module.vti.VtiFilter] Checking is resource exist
12:05:08,977 DEBUG [org.alfresco.module.vti.handler] Resolved file info for 'alfresco/' is null
12:05:08,978 DEBUG [org.alfresco.module.vti.VtiFilter] Resource doesn't exist
12:05:09,021 DEBUG [org.alfresco.module.vti.VtiContextFilter] Checking request for VTI or not
12:05:09,021 DEBUG [org.alfresco.module.vti.VtiContextFilter] Target is VTI request
12:05:09,021 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Process request
12:05:09,021 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Find appropriate filters by pattern for uri='/alfresco/'
12:05:09,021 DEBUG [org.alfresco.module.vti.httpconnector.VtiServletContainer] Process filter
12:05:09,022 DEBUG [org.alfresco.module.vti.VtiFilter] Checking request for VTI or not
12:05:09,022 DEBUG [org.alfresco.module.vti.VtiFilter] Target is not VTI request
12:05:09,022 DEBUG [org.alfresco.module.vti.VtiFilter] Return VTI answer for HEAD request
12:05:09,022 DEBUG [org.alfresco.module.vti.VtiFilter] Checking is resource exist
12:05:09,022 ERROR [org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/alfresco].[jsp]] Servlet.service() for servlet jsp threw exception
org.alfresco.module.vti.VtiInternalErrorException: net.sf.acegisecurity.AuthenticationCredentialsNotFoundException: A valid SecureContext was not provided in the RequestContext
at org.alfresco.module.vti.handler.alfresco.AlfrescoVtiMethodHandlerThrowsAdvice.afterThrowing(AlfrescoVtiMethodHandlerThrowsAdvice.java:53)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.springframework.aop.framework.adapter.ThrowsAdviceInterceptor.invokeHandlerMethod(ThrowsAdviceInterceptor.java:146)
at org.springframework.aop.framework.adapter.ThrowsAdviceInterceptor.invoke(ThrowsAdviceInterceptor.java:131)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:166)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at $Proxy81.existResource(Unknown Source)
at org.alfresco.module.vti.VtiFilter.doFilter(VtiFilter.java:184)
at org.alfresco.module.vti.httpconnector.VtiServletContainer$HttpFilterChain.doFilter(VtiServletContainer.java:273)
at org.alfresco.module.vti.httpconnector.VtiServletContainer.service(VtiServletContainer.java:133)
at org.alfresco.module.vti.VtiContextFilter.doFilter(VtiContextFilter.java:101)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:210)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:174)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:870)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:685)
at java.lang.Thread.run(Thread.java:595)
Caused by: net.sf.acegisecurity.AuthenticationCredentialsNotFoundException: A valid SecureContext was not provided in the RequestContext
at net.sf.acegisecurity.intercept.AbstractSecurityInterceptor.credentialsNotFound(AbstractSecurityInterceptor.java:477)
at net.sf.acegisecurity.intercept.AbstractSecurityInterceptor.beforeInvocation(AbstractSecurityInterceptor.java:355)
at net.sf.acegisecurity.intercept.method.aopalliance.MethodSecurityInterceptor.invoke(MethodSecurityInterceptor.java:77)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:166)
at org.alfresco.repo.security.permissions.impl.ExceptionTranslatorMethodInterceptor.invoke(ExceptionTranslatorMethodInterceptor.java:49)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:166)
at org.alfresco.repo.audit.AuditComponentImpl.audit(AuditComponentImpl.java:275)
at org.alfresco.repo.audit.AuditMethodInterceptor.invoke(AuditMethodInterceptor.java:69)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:166)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:107)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:166)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at $Proxy44.resolveNamePath(Unknown Source)
at org.alfresco.module.vti.handler.alfresco.VtiPathHelper.resolvePathFileInfo(VtiPathHelper.java:136)
at org.alfresco.module.vti.handler.alfresco.AlfrescoVtiMethodHandler.existResource(AlfrescoVtiMethodHandler.java:946)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:296)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:177)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:144)
at org.springframework.aop.framework.adapter.ThrowsAdviceInterceptor.invoke(ThrowsAdviceInterceptor.java:126)
… 21 more