Where is the file located? This is most likely a bad file, not your installation. But unless someone can try it out they are going to have a hard time helping you.
You may wish to install the KLite Codec Mega Pack, which you can get from here:http://www.free-codecs.com/download/k_lite..._Codec_Pack.htm
That will allow you to play most any video format under the sun with windows media player. If you're still having problems, it's most likely the file itself.
Does the file work on other machines?
- My statements do not establish the official position of Microsoft Corporation, and are my own personal opinion. (But you already knew that, right?)