Quicktime Pro upgrade issue

Last week I upgraded Quicktime Pro so I could convert my avi files into a format playable on ITunes. This worked fine last week. However, my avi files still play using VCL, but if I play them through Quicktime Pro I get a red stamp over the screen saying '3ivx Trial' and in the top corner of the screen 'Demo Expired'.
Is this related to Quicktime Pro?

FYI: I've sorted this myself but if anybody else has the issue, deinstall 3ivx from your application folder. This gets rid of the red stamp, but leaves you with no sound. I then ran updates on my the Leopard OSx and everything is now hunky-dory.