Im having problems syncing my server with Fast Download?

My server wont sync to download the file to people who join. This is the message I get:

Fast Download Syncing process has been started for
You may close this window at any time and the sync will continue to run.

Server Error in ‘/’ Application.

Runtime Error

Thanks for any help

Ummm, try removing the / on the start of it, I don’t know.

post the URL that sv_downloadurl is set to