The important error is: 10:05:52,961 ERROR [MainDeployer] Could not create deployment: file:/C:/Program Files/jboss-4.0.4.GA/server/default/deploy/mssql-ds.xml org.jboss.deployment.DeploymentException: Trying to install an already registered mbean: jboss.jca:service=LocalTxCM,name=DefaultDS Apparently, you named the data source DefaultDS. There is already a DefaultDS data source declared in server/xxx/deploy/hsqldb-ds.xml. You will either have to delete that file, of use a different name for the SQL Server data source. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3993894#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...