If WMP is all you have, you may want to go to Microsoft's site to download a patch, sounds like you've got an issue with it, by the way, what version are you using? Anyway, go to:

www.windowsupdate.com

If not, the problem may be the drivers with your burner, try going to the manufacturers' website and make sure your drivers are updated.

As deepblue mentioned, you can use alternative media players, Nero is a good one, however, should you not have it and WMP is all you have, it's a decent program to use for burning, very user-friendly for those who are new to computers. It's sounds like more of a hardware issue than software, when dealing with a problem, you start with the cheapest and easiest fix and then work your way up. Let me know how things work out for you...