Attached Link: "Rock 'em Sock 'em Robots Animation"

It works fine for me (not that my animations are all that great). Could it be the CODEC you are using?

I tend to use DIVX but I know I've used the Microsoft one too.

I have a primitive animation at the 3D Fight Club (a great site for modelers looking to blow off some steam and have a good time). There's a link to it on their main page (probably until Monday... after that you could find it by going into their forum under the weekly scene animation topic... Rocky Animation).