When playing black ops for ps3, I can't join certain game types with certain friends. What do i do?

Was having an issue earlier this week just getting into a party together. So i setup static ip for my ps3 and opened all the ports required on my router. Now we can join parties and play Wager matches and Zombies mode but if i try Team Deathmatch or most of the normal player match types one of us always disconnects when the game is loading. Not sure what to do. My problem is too specific to find a solution typing it into google. Could use some help