[xRyder]

pawn Код:

public OnVehicleDamageStatusUpdate(vehicleid, playerid)
{
    if(GetVehicleModel(vehicleid) == 520 || GetVehicleModel(vehicleid) == 425)
    {
        new Float:health;
        new car;
        car = GetPlayerVehicleID(playerid);
        GetVehicleHealth(car, health);
        if{health < 250) return SendClientMessageToAll(COLOR_YELLOW, "Watch out! A AIR-WAR vehicle is coming down from the sky! Watch your head!");
    }
    return 1;
}

?
You forgot a closing bracket at "...GetVehicleModel(vehicleid) == 425...".