I have to second the comment on the length. In particular, I think the first minute where you show yourself typing in your name to create a new account and then checking email to verify the account, etc is a little unnecessary. At this point in the video, I haven't even seen the product so I'm definitely not sold on creating an account on your site or watching a movie about it. Maybe you can move that part to another video for people that might need help creating an account.

It would also chop off one minute of an 8 minute long demo.

It's cool that you decided to go with Silverlight despite the fact that it's less tried than Flash. Good luck!