16.04.2015, 18:04
OnPlayerEnterVehicle is called when a player starts to enter a vehicle but they're not in it yet so calling GetPlayerVehicleID will return 0. You got the vehicle ID already though assigned to "vehicleid".
Also make sure you have ManualVehicleEngineAndLights enabled.
Also make sure you have ManualVehicleEngineAndLights enabled.