Ok "The man" and Bust3r helped me finding the solution.
Here is a possible solution : http://www.youtube.com/watch?v=VifumdfuW2c
It worked for me.
Anyway I am in too :P
maybe this can help you? also, uninstalling xvid didnt work, but the codecpack in the description worked for me =)
"I've seen enough rule number 34 to burn down a large catholic school" - Bish