Unable to see movie in Quicktime

I downloaded a TV episode last night and I wanted to watch the sample provided to me which is a .avi. I opened the avi and quicktime said I needed something else to view it. I was taken to a page with lots of options, it did not point me to any one in particular. I picked the first one that said I could watch shows with TV like quality which is called On2’s. First, it downloaded as a .sit. I double clicked and it sort of opened--it bounced on my dock, but did nothing after that. I'm not sure what that was all about.

I tried the movie again and it played, but there was no audio or video. Before it just gave me an error message.

Does anyone have any ideas?

Get Mplayer or VLC. There are some .avi movies Quicktime can't play, depending on the codec used.

You probably needed the DivX codec as that is the most common one used currently.

I tried to install the Divx codec and no go, but then I downloaded mplayerosx and it worked wonderfully.
Thanks!