Have you tried configuring your proxy setting? try them on a http proxy. It could also be a firewall problem. If your computer is behind a firewall on version 6 it will not allow you to broadcast a webcam. Also make sure in the 'options' part of msn messenger (go to tools, options) that you have enabled the sharing of your webcam with others (you should tick the box). The same thing happened to me and i have a creative labs webcam. If all else fails delete and re-install the driver for the webcam.