I have a very similar problem. Win2k pro, wmp 9, suddenly NO wma can be played, I got the message requiring DRM upgrade and then "Windows Media Player is not installed properly. Reinstall the Player."
Any solution yet?
P.S. No walmart, another on-line music provider.
I'm going in search of a third party program to allow me to download licenses into WMP 9. If I have any luck, I'll post a link on this thread.