I think it's a DivX problem. from the second site:
Guest
This is a super simple fix. I just went through the same problem. all you have to do is download the divx codec. go to divx.com and download the divx codec. its free and will allow you to work. good luck guys
and
I downloaded DivX (free version) and installed it after experiencing the no video problem with .avi files and it solved it.
diogenysos:Thank you so much....downloaded the VLC player and everything is working just perfectly....I downloaded Happy feet as an .avi this morning and all is working well. Groucho Thank you also for your information and it made me feel better knowing that it wasnt just me LOL. I decided to download the player becuase it would have been easier to get rid off if it didn't work, but it is just great, so I am happy.