How did you install JBoss-4.2.2 GA? Was it through the JEMS installer or did you use the zip archive? Have you modified anything in the server after installing JBoss? Which version of Java is being used and which operating system? When JBoss is starting, you will see the Java version being printed out, post it here. Also, post the log that you see on the console, from the time you start JBoss till you see this error (do this on a clean installation of JBoss which does not have your application). View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4152866#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...