WLM disconnects frequently - how to fix possible UPnP issue?

Hi

For better allround security, I disabled UPnP on my Netgear DG834GT router
and disabled UPnP services in XP (SSDP Discovery Service & Universal Plug
and Play Device Host service).
The idea was to do manual port forwarding on the NAT router, in case I
needed to open something for an application that required UPnP.

This works well but the only problem I have is that Windows Live Messenger
is now frequently disconnecting. It also fails the TCP test (in Advanced
settings). I assume this is because UPnP is disabled...?

The problem is that I wanted to do manual port forwarding for WLM port(s)
but apparently WLM uses a huge range of ports for it to work. I cannot open
all that on the router, surely...? It would be a big security risk to have
all those ports open anyway?

Note: In my WLM advanced settings it says: "You are connected to the
internet through a non-UPnP port restricted NAT" when I'm logged in to WLM.

How do I get WLM to stop the frequent disconnects? MUST UPnP be enabled on
the router (or XP) for WLMessenger to work properly?
If there's any way that WLM can function properly without UPnP being
enabled, please let me know! Your suggestions will be appreciated.

Thank you.