I can't upload my movie to youtube, help please?

I want to upload a movie to youtube but it won't get uploaded properly. The video format is .avi and I know .avi works because i've done it before. The movie is roughly 1 hour and 30 min. For it to upload to youtube it took roughly 5 hours. after the upload finished an error poped up saying "unable to upload" or something like that, i forgot exactly what the error said. I did it on the regular upload and then again on the advanced upload.... Any ideas?