Acessing one's methods

programming flash
1

TypeError: Error #1009: Cannot access a property or method of a null object reference.
at KeyListener/handleKeyDown()

package{
 import flash.display.Sprite;
 import flash.events.*;
 
 public class KeyListener extends Sprite{
  var t:Vehicle;
 
 
  public function KeyListener(stageRef, target){
   t = Vehicle(target);
   stageRef.addEventListener(KeyboardEvent.KEY_DOWN, handleKeyDown);
  }
 
 
  public function handleKeyDown(e:KeyboardEvent):void{
   trace(e.keyCode);
 
 
   switch(e.keyCode){
   case 87://W
   case 38://arrowUP
   t.accelerate();
   break;
   case 39://arrowLEFT
   case 68://D
   t.turnRight();
   break;
 
   }
  }
 }
}

i cant acess Vehicle’s methods from this keyListener class, what am i doing wrong?

the target i’m passing as parameter to this KeyListener is an already instanced Vehicle, and i’m being able to use its methods properly, except on this