Thx for your response. Yes I'm using 'reservation/FlightReservationAccessorBean/remote'. Also, I did a little test. I made a standalone client which tries to access my EJBs, on the jboss 5.0.1, from a remote machine. I packaged the exact jars from Jboss 4.2.3 client dir and put it in the classpath of the standalone client. I get the exact error as before: java.lang.ClassCastException: javax.naming.Reference cannot be cast to com.vsp.reservation.ejb.accessor.FlightReservationAccessorRemote Then, I remove these jars and now package the jars from Jboss 5.0.1 client dir and put it in the classpath of the client. It works great!! So, I think that there is some incompatibilty in terms of different versions of JBoss, as my WAR is on jboss 4.2.3 and my EAR is on jboss 5.0.1. Can someone please let me know a way to go around this incompatibilty?? View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4230921#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...