after browsing for a day i found the answer
to this problem. only posting this in case
people may want a quick fix...

if the video files (.avi, .mpg) do not play
because "class not registered" then you
most likely need to download the

divx codecs. divx is now up to version 5, but backwards
compatible. i got mine here


www.xvidmovies.com

they also have a helpful faq page.