Why isn't my Halo 3 montage uploading to YouTube?

[Joe W]

I have created a montage, and converted it into .mpg format.
But it doesn't upload to YouTube, i have created Tests, which have uploaded fine see my page, http://www.youtube.com/user/TXAvenged
The uploading screen stays up for about 30 mins - 1 hour + and then "Page Cannot be found appears", so i refresh the page, then it says "HTTP 404 Can't be found".
So, i tried ANOTHER test, and that uploaded fine.
Whats going on?
I've checked 'My Videos', and my montage isn't there.
HELP ME PLEASE!

 

[iamperfectnewton]

Probably a problem with Youtube; try uploading to another video host to see if it works (e.g. Megavideo or Veoh)