Az objectet elõbb létre kell hozni!
new obj[MAX_PLAYERS];
obj[playerid] = CreateObject(2438,0,0,-1000,0,0,0,100);
AttachObjectToVehicle(obj[playerid], GetPlayerVehicleID(playerid), 0.018999, -1.539998, 0.929999, 0.000000, 0.000000, 0.000000);
vagy
AttachObjectToVehicle(CreateObject(2438,0,0,-1000,0,0,0,100), GetPlayerVehicleID(playerid), 0.018999, -1.539998, 0.929999, 0.000000, 0.000000, 0.000000);