Anyone else using the DivX Player to watch .avi files?

Since upgrading DivX to 5.1.1 (the free version) from 5.0.2, I find that the Player has an annoying 'buzz' to the sound. It's not there if I use Media Player, so it's the Player rather than the files...

Unfortunately, there doesn't seem to be an easy way to get the old version back.