I have successfully loaded movies to share with a pal, I use Mac BTW, but cannot get to play them, message reads, "sorry we are unable to play this video" or words to that effect. Also i cannot download from it.
I had an issue on Windows 8 where it would me a file exceeded a 100MB limit. I went to the skydrive.com website, and it uploaded without issue. It might just be that the applications have locks to prevent excessive data consumption or something of that nature.