I'm running the latest JBPM Demo setup (jbpm 5.3.0 Final), following the first tutorial (Evaluation sample) in the user guide (Using the Eclipse tooling) and I get the same error as the original poster. It works on the first run after just starting the demo, but after stopping the process and run it again it throws the following error:
ERROR workitem.wsht.GenericHTWorkItemHandler.executeWorkItem - Thu Jul 26 11:21:00 CEST 2012: Error when creating task on task server for work item id 1. Error reported by task server: Task operation request timed out
java.lang.RuntimeException: Task operation request timed out
Any idea why?