I have a few observations: - The JVM 1.6 you have seems a bit old: Java VM: Java HotSpot(TM) Client VM (1.6.0_02-b06 mixed mode) I see at Sun's website they are at "Java SE 6 Update 10 Beta (Build 25)" right now. - JBoss 4 and JBM 1.4 is JVM 1.5 JBoss4 itself doesn't support JVM 1.5 yet. There are few issues with remoting (nothing that would crash it though) and other components at JBoss. I believe they are doing some tests to support JVM 1.5+ soon. So, If you want to keep trying 1.6 even not being supported by JBoss at least update your JVM to the latest update. You can try reporting a bug with SUN if the error still persist on 1.6_latest_update. You definitely should use JVM 1.5. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4159576#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...