Ok so im trying to play the co op maps with my brother via system link but when i try to connect to his game it says the server im trying to connect has a downlodable content that i dont have but the thing is I DO HAVE IT, he already has the map packs on his xbox and he can play them just fine without having to be on XBL but i cant, WTF? HELP PLEASE!!!!!!!!!!!

I tried deleting them and downloading them again but still didnt work