Got the 'Error reading XML' error when claiming the task before completing the task

[tinlinnnsoe]

I am using Activiti engine version 5.17.0 in my java based project. I took all the jar files from the "activiti-explorer.war" folder and using them as library jars in my project build path.

I got the following error when claiming the task before completing the task.

org.activiti.bpmn.exceptions.XMLException: Error reading XML
   at org.activiti.bpmn.converter.BpmnXMLConverter.convertToBpmnModel(BpmnXMLConverter.java:309)
   at org.activiti.bpmn.converter.BpmnXMLConverter.convertToBpmnModel(BpmnXMLConverter.java:281)
   at org.activiti.engine.impl.bpmn.parser.BpmnParse.execute(BpmnParse.java:186)
   at org.activiti.engine.impl.bpmn.deployer.BpmnDeployer.deploy(BpmnDeployer.java:112)
        …………………………………
        Caused by: com.ctc.wstx.exc.WstxUnexpectedCharException: Unexpected character 'K' (code 75) in prolog; expected '<'
 at [row,col {unknown-source}]: [1,1]
   at com.ctc.wstx.sr.StreamScanner.throwUnexpectedChar(StreamScanner.java:639)
   at com.ctc.wstx.sr.BasicStreamReader.nextFromProlog(BasicStreamReader.java:2017)
   at com.ctc.wstx.sr.BasicStreamReader.next(BasicStreamReader.java:1102)
   at org.activiti.bpmn.converter.BpmnXMLConverter.convertToBpmnModel(BpmnXMLConverter.java:306)
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I always noticed this error with following conditions.
(1) Start a new workflow that included 4 approve reject steps
(2) First assignee approve the task
(3) #Restart the application server#
(4) Next assignee approve the second task of previous workflow
At this time, I got the above error.
If the application server is not restarted, it is okay and all of four assignee can approve or reject all of the tasks.

My project environment using following technologies
-> Spring
-> JBoss Seam
-> Spring AOP
-> Ibatis
-> PostgreSQL
-> Application Server is JBoss 7.1

#When Integrating Activiti with Spring MVC and running on Tomcat , It was okay and everything is fine.#
Please help me and give any suggestions.

[jbarrez]

The error seems to indicate that something is wrong at the beginning of your XML. Try to clean it as much as possible to see what is causing the error.

[pakmans]

I was having a similar problem.  I finally tracked the error to a conflict in my jdbc drivers. I had two versions of the postgresql jdbc driver: one for postgresql 8 and another for postgresql 9.  I removed the old one, and now it reads the xml fine.