Don't know how to fix this,but my n900 will randomly decide that it doesn't want to play a video or, more often wont play an internet radio station. It is something to do with the media player. It hangs or gets stuck in a loop or something. There is definitely something wrong with it somewhere.
It can happen 3 times in a day then other times it will go for a week before happening, while .laying all sorts of files.A reboot fixes it but I don't wanna reboot all the time.