Kurt,
I don't think you need a specific codec, I'll double check with Abraham on that. When you click the play track button and it turns into an orange load icon, this is loading the track in to the player. This should play after a second or two. You should also be able to replay the track as many times as you like in the player window.
I'll double check with Abraham on the specs.
Sean Mullen
Creative Director, Creative COW
General Manager, Creative COW StockYard
CEO Rampant Design Tools
http://www.rampantdesigntools.com