Main theme sounds horrible, but all other sounds/music sound great?

Strange problem (actually the ONLY problem I've come across so far). All the sounds and music play just fine EXCEPT the maintheme.mp3. It sounds very tinny/crackly in the game, yet plays just fine in WMP10. It sounds so bad I have to turn off background music.

My system: Dell 1.9MHz , 512MB ram, nVidia 5200 Ultra, Santa Cruz Turtle Beach sound card.

But other than that GC2 rocks!