Yep, just had a discussion on Polyloop forums. Carrara hates .AVI for Vista systems that I read on Google searches, and it just won't work(unknown error on 2nd/3rd frame animations). The other standard BMP/GIF/JPG sequences etc. should work fine though, plus a few other formats/codecs from the net(Im still learning info about them).

 Vista has a few updates to go before its works 100% with alot of things. Carrara may get a fix in C6 I hope. AVI works for most other 3dcg programs though, so its not all Vistas fault.