[JustinAn]

pawn Код:

else if(!IsSultanVehicle(GetPlayerVehicleID(playerid)))return SendClientMessage (playerid, COLOR_YELLOW, "TEXT HERE!"); // <--------- Here is the first(1) Problem!

You had a extra bracket at

Код:

if(!IsSultanVehicle(GetPlayerVehicleID(playerid))) << over here. Take one bracket out, which will look like this.

pawn Код:

if(!IsSultanVehicle(GetPlayerVehicleID(playerid)) - after
if(!IsSultanVehicle(GetPlayerVehicleID(playerid))) - before

Same here for the next one.
Delete one bracket.

pawn Код:

else if(!IsSultanVehicle(GetPlayerVehicleID(playerid)))return SendClientMessage (playerid, COLOR_YELLOW, "TEXT HERE!"); - before

else if(!IsSultanVehicle(GetPlayerVehicleID(playerid))return SendClientMessage (playerid, COLOR_YELLOW, "TEXT HERE!"); after