Unless jbpm-bpel-ds.xml is removed from jbpm-bpel.sar, the data source gets deployed along the jbpm bpel service. However, the web application jbpm-bpel.war also gets deployed before the service and, sometimes, even before the data source. The web app starts the jBPM job executor thread (see the bottom of the stack trace). If the web app is the first to start, The job executor will access the data source before the data source is ready. Note that this is harmless: as you can read from the server log, the thread goes to sleep for a while and then retries: 2007-02-09 14:50:07,590 ERROR [org.jbpm.job.executor.JobExecutorThread] exception in job executor thread. waiting 30000 milliseconds By the time the thread wakes up, the data source is available already. As jgreiner says, deploying the web app separately prevents the error from showing up. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4018329#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...