Can you successfully use the DataSource you have set up from something other than jms? Try setting it up as DefaultDS and seeing if EJB's can use it. I have my doubts... you are using org.opentools... which was replaced in 2.4 with org.jboss.pool.XADataSourceImpl, and I thought (but could be wrong) that the jms jdbc persistence came with 2.4. ( I might have the package wrong, check the manual, it now says)
I'm using JBoss 2.4.1.
I tried the class you suggested but the result was the same.
Seems like nothing is listening to the mySQL port or that you're not allowed to connect to the database. Take a look at this thread: