Wow I'm surprised that G-Spot doesn't know if a codec is needed or not either. Usually it indicates with a message that everthing is OK or that a codec is needed. The only info that might be useful to ya is that it identifies that the AVI file runs on a MPEG4 codec. It also hints that maybe Xvid compression was used. (Xvid is different from DivX but similar).
I'm guessing that maybe the AVI file is corrupt or is in a really unstandard format (which is about as good as being corrupt).
You might want to try this freeware program at this point: http://www.softpedia.com/get/Multimedia/Vi.../Sherlock.shtml
(Sherlock Codec Detective).
It's similar to G-Spot except it atttempts to list all of the codecs installed on your system. I'm guessing that if you run it, it should list MPEG4 and Xvid somewhere buried in listings.
If it doesn't you may want to search for just those codecs and install them.
I have the feeling that Vista comes with MPEG4 support but possibly not Xvid.
If that doesn't work then you may want to consider that the AVI file is corrupt or poorly designed and try downloading it again or getting it from a different source.
Edited by BlackBurst, 02 September 2008 - 03:22 PM.