The videos might be broken but I donīt think so...
http://www.divx-digest.com/software/nimo_pack.html
download Nimo`s codec pack and install it and then try it with your Windows Media player if it doensīt work post which message ou get. Btw Real player sucks and Quick time have problems with a lot of videos, its really the first time that microsoft has done a good job here.
Morgwen