Ted, I have no idea if it would work on Win98. I am only referring to WinXP. What I'm saying is that Azureus' UPnP feature works with my UPnP enabled router and yet I have the WinXP UPnP Service disabled.

You shouldn't have the WinXP UPnP Service enabled unless you specifically need it. Yes I was referring to M$ Messenger. From what you had posted it sounded like it requires the UPnP Service to be enabled. But I don't have first hand experience with that as I don't use M$ Messenger.