"unregistered class" error message

i have just downloaded an .avi file and it simply do not work. when the movie its about to begin, the windows media player shows the message: “unregistered class” (im using a portuguese version, so the message may not be exactly as i wrote above). in portuguese “Classe não registrada”. So, I uninstalled all my codecs, installed the ffdshow and the ac3filter, and yet, it didnt work. so i tryed the K-lite codec pack, the Divx and the X-vid. all i got was the same result: nothing.
my pc is good enough to be the main problem, so the only cause of this problem its a missing codec... please help me out with this stubborn .avi!!!
(sorry if my english is not perfect)

Here is a easy fix for the AVI video playback
Re download your windows media player 9

Then goto http://www.REPAIRVIDEO.com and download the FREE TRIAL PACKAGE, also you will need to download the DIVX player. All should be fine after that:-)

thanx dude... ill try this

Try identifying if the file is real. To do this:

Download/Install GSpot and copy & paste what it says under Video and Audio (right side):

http://www.headbands.com/gspot/gspot221.exe