I use with MySQL and PostgreSQL as datasources in JBoss AS 5.0.x without any issues. Was there a "caused by" clause for your exception? Also, please post the *-ds.xml file for your data source. Remember to place the xml text within code tags (select the text and click the Code button above the editor). And click Preview to ensure htat the formatting is correct before submitting. Also post your persistence.xml file. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4214370#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...