I'm using JBDS 1.1.0.GA and experiencing the same problem. My persistence.xml is located here: C:\java\projects\BETS\exploded-archives\BETS.jar\META-INF There are the following persistence-*.xml files here: C:\java\projects\BETS\resources\META-INF\persistence-dev.xml C:\java\projects\BETS\resources\META-INF\persistence-test.xml C:\java\projects\BETS\resources\META-INF\persistence-prod.xml the build.xml picks up the appropriate file depending on configuration. Must I have the ant explode and/or ant deploy target(s) copy the persistence.xml to this location (C:\java\projects\BETS\resources\META-INF) as well in order to avoid this error??? View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4216641#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...