1. I really think that you need a compilation package of various audio and video codecs : "theorica divx codecs" (click here) and download "The Codecs 3.0 - 9x/ME/2000/XP (English)" unzip, install and play your avi's !Try this (I'm using them and there is no avi that I couldn't watch...)

2. If you get the corrupt file message then you need to rebuild the file index...(only for avi's)
Look at the last message in his thread...
Click Here (is a link to a similar problem)

3. Post a reply so I know if it worked !!! (here on this thread NOT private messages !!!) by doing this you can help other people who are having the same problemes !!!