I know this sounds stupid, but bear with me here.
I am playing a huge Earth map with 15 civs, yet when I go to my foreign advisor screen there are only x8 civs. The missing civs can contact me, establish an embasy, ect., but I can't trade with them. What seems to be the problem?
i had the same problem, and was annoyed when i killed one of the guys on the foreign adviser screen to see if i could get another civ to appear there and it just left it blank, bah