Plug and Play (UPnP) not working w/ Trendnet firewall appliance

[anonymous]

I have a Trendnet firewall appliance (tw100-s4w1ca) protecting my home network. Behind that firewall I have a number of computers including an Ubuntu system that I use as a MythTV server. On the Ubuntu box I run Transmission (a Linux BT client). Transmission is able to use UPnP to configure the router to allow incoming traffic (incoming connections, seeding, etc.) and it works just fine.

I also have a windows box with uTorrent 1.8.3 installed on the same network. However, uTorrent does not seem to be able to configure the router to allow incoming connections.

Any ideas why this works from the Ubuntu box but fails with uTorrent on Windows?

Thanks,

- James