Well now you are jumping to another problem.
Try to add the jar file to the class path of your project.
If you are facing further problems which are not related ot jbpm, make sure to post a new thread and in the right place.
p.s.
- Try to add an end state to you process, cause you "may" face further problems.
- executionContext.leaveNode(); // to leave the node after action execution
Regards