There is a version of WMP for mac.
I have both WMP and iTunes on my PC's and my old G4, because I have MP3 players and iPods. Slightly different topic - iGadget is a great program to avoid having to sync the iPod everytime you want to put something on or take something off.
You could try reformatting the clip -
http://forums.sandisk.com/sansa/board/message?board.id=clip&message.id=3744