let's see...did u add new custom civs into the mod, with no leaderheads?
i think the diplomacy text is 'cos of the new custom civs without any diplomacy dialogues programmed into the diplomacy.txt file. i added the scottish civ (with sween32's leaderhead) and realised this, but i was just too lazy to add the text, so i just let it be.
but i had no prob with the foreign advisor screen.