[TheDominator]

It seems as if your using strcmp and Zcmd to use for commands which isn't possible, what you should try is:

pawn Код:

public OnPlayerCommandText(playerid, cmdtext[])
{
    if (strcmp("/weapon", cmdtext, true, 10) == 0)
    {
        if(!IsPlayerAdmin(playerid))
        return SendClientMessage(playerid,-1,"You are not logged into Rcon"); //    Sends client message that he     is not logged into rcon
        GivePlayerWeapon(playerid,38,500); // Gives player weapon if he is logged into RCON
        return 1;
    }
    return 0;
}

I am sorry if it doesn't work but at the moment I am unable to test it due to the fact that my GTA_SA has suddenly decided it wants to crash.