The author of that flash credited everyone but the musicians. That's just sick.
I had that happen to me once. Someone used my piece in a game and it got several hundred thousand plays. People were posting on yahoo answers asking who wrote the music. It wasn't until months later, after all that lost exposure, that someone who recognized my music contacted me.
I hope you find out who made the music and contact him. He probably doesn't even know that his music was used in a game, or that the author of that game is probably making money from a sponsor with it.