the problem on COD4 is not down to your conection, i use a Netgear wireless router, i never get a signal strength less than 80%, and i cannot join accept an invite unless i am in the lobby.

We have all experienced this, it was driving sfjp mad for a while.

Remember we bumped into each other in the lobby, we managed ok then, its just when you are already on a agme, it wont let you accept an invite.

I think............