webcam Windows Messenger v. MSN Messenger

I would dearly love to clear up a few questions. I have
XP Pro, Windows Messenger 5.0, a Logitech "QuickCam
Messenger" video camera, all behind a D-Link DI-604
broadband router (UPnP) managing my ADSL Internet
connection. MSN Messenger is not installed on my
computer. The issue arises because my kids cannot
initiate a "webcam" Windows Mesenger session with friends
(they use MSN Messenger 6.1). My kids log in as "power
users" on XP Pro, not as "administrators".

1. Is it true what my kids tell me: Windows Messenger
users can't engage in a "webcam" session with MSN
Messenger users? Does the fact that we have XP Pro and
the friends run Win98SE make a difference?
2. Do my kids have to be logged in as "administrators" to
have "webcam" sessions with friends over the Internet?
3. Does my broadband router have anything to do with this?

I would be grateful for answers to these questions. More
important still, I would be grateful for tips on how to
get my kids using their Logitech webcam to have video
meetings over the Internet with their friends.

Thank you very much.