Routers / Switches :: Wireless Won't Allow Network Gaming?

I am currently playing Football manager 2011 with a friend via a network game. The game will work perfectly if I connect my Laptop to the modem directly and bypass the Wireless. However if I try to play the game while connected to the wireless then my friend is unable to connect to the game. This is becoming an issue as for me to be able to play the game I have to turn the wireless off which is getting on the nerves of other family members