What you just now posted has nothing to do with the original problem in your first post. Please focus on the initial problem and do not mention additional problems. You can start a new post about this new problem, and I suggest you do it in the JBossAS5 forum (http://www.jboss.com/index.html?module=bb&op=viewforum&f=287), but only after you have looked through that form for similar posts that might already answer that problem. Getting back to the original problem. You say that after you make the changes I suggested to *-ds.xml that you are still getting the class not found exception, is that correct? I do not use SQL Server, but I do use MySQL and PostgreSQL, and 5.0CR1 did not have any problems finding the drivers for those databases. So there must be some simple configuration error you are doing. Here is what I would do. First I would list the classes in the JDBC driver JAR file using "jar -tf xxx.jar" and verify that the class name is correct. Next I would determine if the SQLServerDriver class requires other classes (sometimes the problem is with a referenced class, and not the class reported in the class not found exception). Finally, in the working 4.2.2 version, I would set the -verbose:class JVM option and determine where the SQLServerDriver class is being loaded. I would then add -verbose:class to 5.0CR1. One of those things usually helps me to pinpoint the issue. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4165978#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...