Nimo is a dangerous Codec pack. At least I had a problem with one of the Codec's I don't remember witch but I had to get rid of one for my system to work right. It's been a few months since that problem though. I believe I had v9 beta 1 of nimo's codec pack. The Beta is probably where I ran into problems.
If you want a program to actually tell you what codec you need for a video file, then get VirtualDub (it's free). I will never cease to suggest this program... you'll probably find reference to it in half of my posts!