[Jasno]

Легче SetTimerEx("PlayerTimer", 500, false, "i", playerid);
public PlayerTimer(playerid)
{
if(!IsPlayerConnected(playerid)) return 0;
SetTimerEx("PlayerTimer", 500, false, "i", playerid);
return 1;
}

Или

public PlayerTimer(playerid)
{
if(!IsPlayerConnected(playerid)) return KillTimer(PlayerInfo[playerid][pTimer]);
return 1;
}