My game insta-crashes when my friend joins my server

[toadchum.]

Hello! When i try to host a game with this on gameranger, my game immediately crashes when my friend joins, i can play the campaign normally, i can play multiplayer with no one in the server, but the second my friend joins, game just closes. Same for when i try to join HIS server.. Just wanna play this masterpiece, if anyone can help it'll be appreciated. (there are no error messages that pop up once it crashes btw)

[Anyder]

Hello,

Have you tried using out tool for internet gaming? Check it out here: http://info.swbfspy.com