Hello,
This is because by default for the Jboss build target we remove the "portlet-api-lib.jar" from the resulting WAR file as it is already including inside the jbossPortal deployment. To fix the error, edit the file:
projects\web-client\project.properties
you'll see the line:
webinf.lib.delete.jboss=log4j-1.2.8.jar,portlet-api-lib.jar,myfaces-api.jar,myfaces-impl.jar
change it to:
webinf.lib.delete.jboss=log4j-1.2.8.jar,myfaces-api.jar,myfaces-impl.jar
And rebuild as you did before. This should add back in the portal JAR file which is needed to compile some of the JSP files (even if they do not access the portal there is some code in the JSPs which must be there for both)
Thanks,
Kevin