This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
If you get a javax.naming.NameNotFoundException error, you have either not installed the context.xml file correctly, or have used a different name in the context.xml <Resource> element's "name" attribute to what you are using in your Context.lookup() call.
I think some more configuration is requird to use the context.xml file..