From what you said you are most likely using Vista or 7. Either way can you explain what you are doing in multiplayer? Are you double-accounting? What servers are you playing on static (SemiPro::Judo)? Does it happen at any specific moment? (When you join a game, when it's your turn to play, when someone else joins, when a player wins or loses by DQ, when you win a match and a new person is ready) What SlipAnc asked too, what version of Toribash are you running?