Now why would you wait two weeks? Struggle is important, but a week of struggle is good enough.
Okay, looks like a JNDI problem. What is the ACTUAL name your datasource is bound to your JNDI server with? You don't know? Well, find out.
WebSphere provides a utility called dumpnamespace.sh, or .bat, depending on your operating system. Use that utiliy to dump your namespace, and see the actual name used by the datasource to bind itself to the JNDI server. Then, ue this name during the lookup.
Of course, you shouldn't be using that actual name in code, but rather, a resource reference, so once you get it working with the acutal name, use a reference instead. Here's a little tutorial on JNDI naming with WebSphere, which includes information on resource reference, and topology dependent JNDI names:
http://www.technicalfacilitation.com/get.php?link=naming What development environment are you using? WebSphere Studio Application Developer (WSAD) and IBM's Rational Application Developer(IRAD) both provide a JNDI Exlporer. While it's designed to connect to the local test envirnoment, you can change the URL/PORT to connect to and explore any JNDI server. I would HIGHLY recomment attacking your application server with this JNDI explorer tool. You can type JNDI names directly into it, and find out if the JNDI name you're using is valid or not. Any name that works in the JNDI explorer will work in your running code.
Good luck. If you still have problems, post again, and in less than two weeks time. Include a little info on your environment, such as version, development environment, and OS.
Cheers!
-Cameron McKenzie