[Konstantinos]

I told you any code out of callbacks is invalid and you re-added outside.

pawn Код:

public OnPlayerCommandText(playerid, cmdtext[])
{
    if(!strcmp(cmdtext, "/help", true))
    {
        SendClientMessage(playerid, 0xFFFFFFFF, "To be updated.");
        return 1;
    }
    // other commands
    return 0;
}

public OnPlayerEnterVehicle(playerid, vehicleid, ispassenger)
{
    // code..
    return 1;
}