First of all: You need asm.jar in bin/ also. Second: You should use JDK-1.5 instead, since JDK-1.6 isn't officially supported in AS-4.0.x Third: JBoss Profiler 2 was designed to be used together with AS-4.2 and AS-5.0. 4th: When you are done - after startup f.ex - just issue: Client stopProfiler Client getSnapshot 1 Client load file.jps See README.txt for details... Otherwise you are good to go :) Hope this helps ! View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4122739#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...