windows media center problems!

i have been using it to burn avi movies to dvd and now its not even playing the movies anymore and comes up with a screen saying that the movie can not be played and go’s on saying that the path of the videos are messed up and they cant play them! I tried double clicking on them in the folder out side of the media center and it gos to media center and says the same thing, it used to work perfect! Anyone have any idea whats going on with it or now how to fix the problem it would be deply appreciated! sorry if i posted this is the wrong forum aswell!