I am a total newbie to JBOSS and trying to run it on my computer. I always get this message (below). I have just downloaded JDK (1.5.0_07) and run.conf is pointing to it as well. What do you think I am doing wrong. Please help. C:\PROGRA~1\JBOSS-~1.GA\bin>run =============================================================================== . JBoss Bootstrap Environment . JBOSS_HOME: C:\PROGRA~1\JBOSS-~1.GA\bin\\.. . JAVA: java . JAVA_OPTS: -Dprogram.name=run.bat -Xms128m -Xmx512m -Dsun.rmi.dgc.client.gcIn terval=3600000 -Dsun.rmi.dgc.server.gcInterval=3600000 . CLASSPATH: C:\oracle\ora92\jdk\lib\tools.jar;C:\PROGRA~1\JBOSS-~1.GA\bin\\run. jar . =============================================================================== . Exception in thread "main" java.lang.UnsupportedClassVersionError: org/jboss/Mai n (Unsupported major.minor version 48.0) at java.lang.ClassLoader.defineClass0(Native Method) at java.lang.ClassLoader.defineClass(Unknown Source) at java.security.SecureClassLoader.defineClass(Unknown Source) at java.net.URLClassLoader.defineClass(Unknown Source) at java.net.URLClassLoader.access$100(Unknown Source) at java.net.URLClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClassInternal(Unknown Source) Press any key to continue . . . View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3963728#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...