freind list Error

i wanna add someone in crossfire but when i try to add him a message pops up telling me dat he is already in my freindlist and when he try to add me da same msg appear.
he is actually in my freindlist but he always appear as if he deleted me as he appeared to be offline eve when i was takin' to him and i can't delete him and add him again so plz help me cuz we wanna add each other.