Hi, Thanks for your answer. When going through my initial poste I noticed that i forgot to mention the JVM used. Both server and client are running on the same JVM version (1.5.0_06-b05). Now to the results of your suggestions. Port: Our server is listing on Port 1299 (we do not use the default config). As we can perform the lookup of the remote object without getting an exception the server is listening on this port. java.naming.factory.url.pkgs: I tried "java.naming.factory.url.pkgs" with and without equal sign, but it had no effect whatsorever. PortableRemoteObject.narrow: I inserted PortableRemoteObject.narrow but still the call on the remote method fails. As I see it there must be another problem. It could be related to RMI or even on a lower level as the error message states "Problem establishing socket connection". Another reason could be that we are using the wrong libraries. Currently we are using the following libraries (all provided with JBoss 4.0.4GA): jbossall-client.jar jboss-ejb3-client.jar jboss-aspect-library-jdk50.jar jboss-aop-jdk50.jar Any further help is greatly appreciated :-) Regards Christoph View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3962727#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...