Sorry to go off thread but to reply to toorop, it sounds like you've hit the same issue as me (Cannot make Evaluation example work consistently in Eclipse).
I've not had time to revisit it since, but I think it may be something to do with the example code (ProcessTest) not disposing of the human task at the end of the demo.
Not very helpful I know, but at least you know you are not alone :)
Andy McC