Hi PeterJ: Thanks for your high attention. It is really strange, I just want to run the Jboss server again to get the detail informations before the Exception, but the server can start with no execption. I did not do anything for it. I list the detail informations that you asked as following: JBoss version is "jboss-4.0.4.GA-Patch1" Java version is "1.5.0_08" operating system is "Windows Xp(sp2)" I got a "jboss-4.0.4.GA-Patch1-installer.jar" from website, and used "java -jar" command to install. Installation path "E:\jboss-4.0.4.GA" Step by Step: 1.I selected "ejb3-cluster" option for installtype 2.I selected all the packs 3.Jboss server/xxx configuration name: "all" 4.I selected four options for "JMX Security" Hope you can find something. : ) Thanks again View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4033574#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...