A couple of times I've been unable to open ports from my computer (also Windows 7 64bit), but most times it works fine.
Thats typical for UPnP, a fallback would be NAT-PMP which isn't supported by older routers by telcos usually give you one for free every few years (at least here we have 5 different routers now)
Shitlord by trade and passion. Graphics programmer at Laminar Research. I write blog posts at feresignum.com
