Hi!
I had the same problem. It's because of the wrong package definition. You need to edit the properties of the process definition : click in the background of the diagram in eclipse and change the package value to "defaultpackage" for example, then re-commit the file into guvnor.
After that I had other problems like you can see in my post :
http://community.jboss.org/thread/167900?tstart=0
If you find something about that, can you tell me ?
Regards
IT-Student