In attempting a small experiment, I seemed to have solved the issue. Simply adding el-ri.jar to the server/default/lib directory in my JBoss 4.2.0.GA install causes the NoClassDefFoundError to no longer occur on restart/shutdown. The idea came from Pete's statement that the el-impl.jar is not shipped with 4.2. I'm not sure if this will cause other unwanted problems going forward, as I haven't tested the install or application much. Carl View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4064139#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...