It looks like you have a different jboss-messaging-client.jar somewhere. this serialVersionUID clash is a sign that you have different jar versions somewhere. 14:59:15,275 INFO [STDOUT] 14:59:15,275 ERROR [SimpleMessageClient] | JNDI lookup failed: javax.naming.CommunicationException [Root exception is java.io.InvalidClassExc | eption: org.jboss.jms.client.delegate.DelegateSupport; | local class incompatible: stream classdesc serialVersionUID = -1362079381836473747, | local class serialVersionUID = -1723908125830723356] | | View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4056559#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...