Hi guys, this post here might fix your problem. http://community.jboss.org/message/590059 (it fixed mine at least).
In particular,
- I am using jBPM 5.2.0-Final. I installed the Eclipse JBoss Tools for Helios and found the Drools plugin bundled with it is out-dated. So I un-installed the JBoss Tools and install http://download.jboss.org/drools/release/5.2.0.Final/droolsjbpm-tools-distribution-5.2.0.Final.zip instead.
- Human Task service and H2 running.
- In Eclipse, switch on the Build Automatically under Project. Then make sure when you edit the bpmn file and it automatically gets copied to the target directory.