I had the issue that others reported where it becomes a small window (with title "ActiveMovie Window") and becomes unplayable. You can switch away from the small window to the main game to see it again, but it's stuttery and will randomly switch you back to the small window.

I fixed it by doing the wma -> mp3 rename fix for the background music. My guess is that the the little window is the game failing to play the wma files. Every time it plays it, it'll spawn a window. So presumably any of the other background music fixes should also work.