.avi osx and quicktime!!!!

I have downloaded an .avi file and 'quicktime will not play it. It says it cannot locate the correct compressor. But I have the .avi file import turned on in quicktime settings. I am running osx. It seems to be a really cool movie file and I want to watch it! I have the newest divx in the right directory, but maybe I need another compressor? Please help!!!!