you missing the jbossall-client.jar from your classpath.
Thank's a lot for your post!
I was including jbossall-client.jar in my classpath but you made me think that wasn't the jboss3.2.3 version but the older jboss3.2.1, the one used when the application was developed.
just in case someone experiences the same problem I had:
On one machine the root exception was not a ClassNotFoundException but the output was the following:
"javax.naming.NamingException: Failed to retrieve Naming interface. Root exception is java.io.IOException: Server returned HTTP response code: 401 for URL:"...
On another machine the exception was "ClassNotFound".
As described above the problem was a wrong version of the jbossallclient.jar and replacing it with a new one solved the problem in both cases.