Which exact version of JBoss are you using? Your first post says its 5.0 CR1, the first few lines in the log show that the folder name of JBoss Home is JBoss-4.0 and the Started message shows its 5.0 CR2. Are you sure, the JBoss installation is clean? As for the exception, are you packaging any jar containing the org.apache.xerces.* package? If yes, then remove it from your application packaging. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4198898#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...