I have the same configuration you have, at least as far as what you have reported, and 4.0.5 works fine for me. I am suspecting either a corrupt JVM installation (low probability) or a bad driver/library (high probability). Could you try the following: 1) Run JBoss AS 4.0.5.GA with 1.4.2 JVM 2) Install and run JBoss AS 4.0.4.GA with JVM 1.5.0 and again with 1.4.2 JVM If you get any of the above combinations working, use the listdlls utility from www.sysinternals.com to get a list of DLLs loaded into the JVM by entering: listdlls java Post the results. Whatever is causing the problem should show up in that output (unless you have a corrupt system DLL). View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3982401#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...