[Johnj]

Start the game
Click on the MULTIPLAYER door
Click on START GAME
Choose a game type
Now your at the Start Game Menu
...Do set Maxplayers to 8.
...Do set a score, or time limit, or both.
...Do set a Game Server Name.
...DO NOT set DEDICATED SERVER
Click on START GAME

Now call your buddies and have them try to join with Connect to IP Address. Stay on your computer, running around on the map, for at least twenty min.