Hehe, No problems
Right, another thing to try.
If you go to the Programs menu where it should have installed itself, there should be a DIVX settings program called "Decoder Configuration Utility"
Go onto that, and they'll be settings corrosponding to how to play the video, for instance video quality and sound quality that mght improve the speed its playing at.
It could also be Windows Media Player doing it though. If you stop the video, and play it again, it might correct itself and get into sync.
I hope this helps