Hi Al! Thanks for your reply. Unfortunally the error remains.. persistence.units ear=system.ear,jar=accountsystem.jar,unitName=AccountSystem accountsystem.jar references shared-susbsystems.jar with a Class-Path attribute in the manifest. The Entity EJB3 classes are in the shared-subsystems.jar and the persistence.xml is the accountsystem.jar's meta-inf directory. The classes loads. In my bean I do this on the first line in the method: log.info("This: " + this.getClass().getClassLoader()); log.info("User: " + user.getClass().getClassLoader()); And the result is: [AccountSystem] This: org.jboss.mx.loading.UnifiedClassLoader 3@19a639b{ url=file:/C:/Program/jboss-4.0.4.GA/server/default/tmp/deploy/tmp5726 0system.ear ,addedOrder=51} [AccountSystem] User: org.jboss.mx.loading.UnifiedClassLoader 3@19a639b{ url=file:/C:/Program/jboss-4.0.4.GA/server/default/tmp/deploy/tmp5726 0system.ear ,addedOrder=51} Same classloader... I don't understand.. Thanks anyone for anyhelp!! View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3979391#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...