help needed with my bush divx dvd player

I have a dvd player that can play divx movies. I have downloaded some movies in avi format that the audio has been out of sync. I used avi mux to re sync the film but when i make a data dvd and play in my divx player the film will only play for a few seconds then it
cuts off. I noticed if i dont use avi mux to resync the films they play ok.Any idea what is causing this problem. 1 more thing i need to ask about is my divx player is a bush dvd2080divx player i noticed sometimes when i play back avi files on it it will go in slow motion for a few seconds when playing scenes and then correct its self.Any help on these issues would be great thanks