new Player, Score;
if(IsPlayerConnected(playerid) && IsPlayerConnected(Player))
{
    if(sscanf(cmdtext, "ui", Player, Score))
    {
        SendClientMessage(playerid, CHANGECOLOR, "Usage: /setscore [playerid/playername] [score]");
    }
    else if(Score < 0)
    {
        SendClientMessage(playerid, CHANGECOLOR, "Usage: Invalid score");
    }
    else if(Player == INVALID_PLAYER_ID)
    {
        SendClientMessage(playerid, CHANGECOLOR, "Usage: Invalid playerid");
    }
    else
    {
        SetPlayerScore(Player, Score);
    }
    return 1;
}

dcmd_setplayerscore(playerid, params[])
{
        //If you use enums, then use this line or else just keep IsPlayerAdmin.
        if(PlayerInfo[playerid][Level] >= 2 || IsPlayerAdmin(playerid))
        {
            new toplayerid, score;
            if(!sscanf(params,"ii",toplayerid,score))
            {
                if(IsPlayerConnected(toplayerid))
                {
                    new names[MAX_PLAYER_NAME], msg[64];
                    GetPlayerName(playerid, names, sizeof(names));
                    format(msg,sizeof(msg),"Administrator %s set your score to %i.",names,score);
                    SetPlayerScore(toplayerid, score);
                    SendClientMessage(toplayerid, 0xCCFFCCFF, msg);
                    PlayerPlaySound(toplayerid, 1057,0,0,0);

                    GetPlayerName(toplayerid, names, sizeof(names));
                    format(msg,sizeof(msg),"You have set %s's score to %i.",names,score);
                    SendClientMessage(playerid, 0x00FF00FF, msg);
                    
                } else return SendClientMessage(playerid, 0xFF0000FF, "Error: Player is offline.");
            } else return SendClientMessage(playerid, 0xFF0000FF, "USAGE: /SETPLAYERSCORE [Player ID] [Score]");
        } else return SendClientMessage(playerid, 0xFF0000FF, "You are not authorized to use this command.");
        return true;
}