OK, somebody call me a n00b, but how do you know if you have an open NAT? All the guides I could find on the web seemed to be out of date.
go to crossfire mode and before you look for a match look towards the bottom of the screen and it will say natpen/moderate/strict depending on what you have
If it ain't open, just restart your router. I was playing all last week with Strict till I remembered that :?