What exactly are you doing? what programs are you using? Are you trying to post the raw AH film viewer segment or make an actual movie?
This is what I do when I make a film:
1) Open up the original in-game film with AH film viewer
2) use FRAPS to basicly re-record the original film to show whatever camera angle, position, or segment that you want. FRAPS is a free download program that shows you your frame rate and records gaming footage.
3) open up Windows Movie Maker. This is where you can upload music, add graphics, and arrange the FRAPS footage any way you want it.
4) when you finish, save the movie to "my computer". This will allow you to open it up and view your film in Windows Media Player if it set as your default film viewer.
5) upload your film to a file hosting site such as mediafire.com, and post the link on the forums here for the rest of us to watch.
Good Luck. it may be frustrating to get the hang of, but is very fun to create and design.
Here is the link to a movie I made about a year ago following these steps.
http://www.mediafire.com/download.php?gwm32ywmyzz