First, do not ask new questions at the end of existing posts, especially not posts that are 4 years old! Second, try using JDK 1.5, 1.6 is not yet qualified for use with 4.0.5 (I have seen some people use it successfully and others have all kinds of problems, so your best bet it to use 1.5). Third, the exception means that your remote clients are not using the same version of the jar files as what is available in the app server. Most likely, the clients are still using the older jars. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4053583#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...