Webcam not working with windows live messenger beta

You are Unable to Initiate a Video Call or Video Conversation in Windows Live Messenger after Upgrading to the Latest 2009 version (build 14.0.8050.1202)
Note: This information only applies for users who have the McAfee Site Advisor.

SYMPTOMS:

When trying to initiate a Video Call or Video Conversation in Windows Live Messenger 2009, one the following errors is encountered:

“We couldn't start your camera device. Please check that your camera is not currently in use by another program, and then try again.”
"Messenger is not available right now. Please try again later. (0x8ac70202)"
"Messenger is not available right now. Please try again later. (0x8ac70013)"

When trying to run the Audio Video Setup this error is encountered:

“We are unable to run the Audio Video Setup”

TROUBLESHOOTING STEPS:

This issue has been determined to be caused by a compatibility problem with Windows Live Messenger 2009 and the McAfee Site Advisor. McAfee is working on a patch to address this issue, but until it becomes available, you may try the posted workaround on their website at:
http://service.mcafee.com/faqdocument.aspx?id=TS100601


Solution found at:http://messenger-support.spaces.live.com/blog/cns!8B3F39C76A8B853F!14323.entry

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I fixed it!
Your webcams are being blocked by a program on your computer, quite possibly a firewall.
On my laptop it was McAfee. I had a 60 day free trial which I think came with my laptop.
If you go to the start menu, control panel, control panel home, uninstall a program and then double click McAfee. You then have to tick all of the boxes to uninstall it entirely. This will allow you to use your webcam with MSN, but if you havent downloaded/purchased anti-virus software your computer will be at risk.
If you dont have any anti-virus software I would get some :)
You could find a free program to download from the internet or you could buy one.

Hope it helped!