Check that UPnP is enabled on your Netgear 1st. If it's not enabled, then enable it, restart LW & see how it goes. If UPnP is already enabled, then yes ... consider doing the port forwarding. Actually Peerless might be a good one to ask if NFW is the problem.

UPnP has always been enabled but actually I'm not too sure that NFW is the problem because isn't it odd that it didn't object to LW when I removed it from Program Control? It looks as though it wasn't making any difference in the first place doesn't it? Is NFW capable of logging actions taken by another firewall?
Sorry if that's a daft question but I'm very new to this!

Actually, I've just had a look at the General Rules on NFW and it is set to block Windows 2000 SMB, EPMAP, UPNP port 5000 & UPNP port 1900 so is that OK?