the upnp will open the ports automatically... None have to be opened manually... I found the option to turn this on in my administrative options in my router...
There was alot of concern with regard to security and upnp; however, keeping the ports open all the time is much more risky...
This article mentions your router (I think)
http://www.microsoft.com/windowsxp/e...december24.asp
Once you get it working, let me know if it continues to work...
Thanks,
Scott
PS, if your going to open ports manually, you would have to open a range of ports. I.E. 5555 to 6666. I forget the range but it is described in the windows messenger help section. Again, this range is wide and it allows for a large gap in your firewall that stays open. This allows your computer to let other computers know that this gap is available for use... (one can see the danger in doing this)
UpNP is a much safer route to follow because the ports only open when needed...