Finally found my answer. This is a simple classpath issue. The jse client that I am running needs the following classes in it's classpath (including the jar which contains the service interface on whom methods are to be called) jbossall-client.jar jbossws14-client.jar activation.jar xml-apis.jar xercesImpl.jar mail.jar jboss-backport-concurrent.jar jbossretro-rt.jar It is frustrating that it gives such a vague exception providing no clue as to what might be the issue. I got the clue from ExpertsExchange http://www.experts-exchange.com/Programming/Programming_Languages/Java/Q_... Thank you folks. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4003567#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...