You might also want to look into other DivX players. I like Global DivX myself. (Although I'm using the 0.91 version). I've found the WMP and The Playa 2.0 Alpha don't always play the files correctly.
Also, when installing the codecs, I always install the 3.11 version and then install the 4.x version. And during the setup of 4.x, I choose to not have the 4.x play all the 3.x content. Some DivX files won't play under anything but 3.x. Although, hopefully, newer DivX files won't have these problems once everyone uses the newer version.
Being right doesn't matter if no one listens.