Ronster316 on 26 April 2009
You both need to ensure local co op is enabled in the options menu.
When i first bought the game i turned off co op in the options because i didn't want people joining my game whilst i was playing it for the first time.
Then when my buddy used to invite me to his game i couldn't join until i enabled co op again.
Someone must have co op disabled, thats all i can think of.
