I was getting something similar and needed to point my runtime classpath at jboss/client jars. | [java] javax.naming.CommunicationException [Root exception is java.io.InvalidClassException: org.jboss.remoting.InvokerLocator; local class incompatible: stream classdesc serialVersionUID = -2909329895029296248, local class serialVersionUID = -4977622166779282521] | [java] at org.jnp.interfaces.NamingContext.lookup(NamingContext.java:723) | [java] at org.jnp.interfaces.NamingContext.lookup(NamingContext.java:588) | [java] at javax.naming.InitialContext.lookup(InitialContext.java:351) | [java] at client.EjbClient.main(EjbClient.java:37) | [java] Caused by: java.io.InvalidClassException: org.jboss.remoting.InvokerLocator; local class incompatible: stream classdesc serialVersionUID = -2909329895029296248, local class serialVersionUID = -4977622166779282521 | [java] at java.io.ObjectStreamClass.initNonProxy(ObjectStreamClass.java:546) | [java] at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1552) | [java] at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1466) | SO Here was the fix to make sure the jboss/client/*.jar is in classpath first. This was a snippet of the ant task for running my client. | <fileset dir="/usr/local/jboss/client"> | <include name="*.jar"/> | </fileset> | </path> | View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4013062#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...