[grand.Theft.Otto]

Doubt this will work but, try setting it for max players:

pawn Code:

public GameTime()
{
    for(new i = 0; i < MAX_PLAYERS; i++)
    {
        if(GameSeconds > 0 || GameMinutes > 0)
        {
            GameSeconds--;
            if(GameSeconds <= -1)
            {
                GameMinutes--;
                GameSeconds=59;
            }
            new TimeString[14];
            format(TimeString,sizeof(TimeString),"%02d:%02d",GameMinutes,GameSeconds);
            TextDrawSetString(Textdraw0,TimeString);
        }
        if(GameSeconds == 0 && GameMinutes == 0)
        {
            OnGameModeExit();
        }
    }
    return 1;
}