Hi, I think this is related to http://jira.jboss.com/jira/browse/JBPM-949 which we upgraded to 3.2.1 to get around. We changed our code to specify a business key when creating a new process instance. Now our 2nd and subsequent processes start OK, but the subprocesses that they might fork fail with the same problem. How do we set the business 'key' for a subprocess, as it is not inherited from the parent process? Currently we can run only one instance of a subprocess or this problem will bite us! We don't want to relax the constraint in the database... View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4068778#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...