Broadcaster demands password

QuickTime Broadcaster shows the video feed coming in, and when I hit "Broadcast", I get this dialog:

"Enter username for Streaming Server at <my ip address here> :"

And prompts for a username and password. The username and password I selected for QuickTime Streaming server does not work.

I left blank.

I tried my computer name and pasword.

I tried my network name and password.

BUT, it won't broadcast until I enter a good username and password. But I don't know what it's asking for.

Can you advise?

Thanks