The Reference guide included with the 2.6.1 bundle includes the system requirements and mentions that both JDK4 and JDK5 are supported. I am constrained to JDK4 and when I install and run jboss-portal-2.6.1.GA.zip on my machine I get an UnsupportedClassVersionError. This would appear to proclude the use of JDK4. As I am a new JBoss user (evaluating at this stage) I would like to be pointed to some simple instructions for operating the portal on JDK4. If someone would take the time to tell me what I am doing wrong (or confirm that the documentation is incorrect or incomplete) and the steps I need to take to get it running (on JDK4) I would be very appreciative. Thank you, View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4074227#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...