Denon 1920 - problem with divx audio

I have just started using my denon 1920 to play divx movies. I tried a couple of divx and the video seemed to be play just a bit to slowly at times but sound is fine. Now I've just burnt a third dvix onto a dvdr and I get the image but not the sound. On my computer this divx plays fine with windows media player. Any answers? Do I need to upgrade the codec on the denon 1920. It is a recent player though. If that is the case how do I install the latest codecs on the denon 1920?