I am 99% sure the server crashes have something to do with people shooting other players or zombies. I do know for a fact the server crashes are caused by the shooting action. On 4 separate occasions of playing .61 exp I have experienced this. I saw a player get killed by a player with a shotgun and the server instantly crashed. On the other occasions I have heard faint gunshots in the distance then the server crashes right after hearing it. I hope this helps.