title: AS3 : #1009: Cannot access a property or method of a null object reference
body: <p>I would like to ask for your help with my code. It compiles ok but upon reaching the below code it throws this error :</p>
  
  <blockquote>
    <p>Error  #1009: Cannot access a property or method of a null object
    reference at
    HiddenObjects_fla::MainTimeline/myFunction()[HiddenObjects_fla.MainTimeline::frame12:9]</p>
  </blockquote>
  
  <p>I do not have a frame 12 in my main timeline. </p>
  
  <pre><code>import flash.display.Sprite;
  import flash.events.*;
  
  addEventListener(Event.ENTER_FRAME,myFunction);
  function myFunction(event:Event):void {
  var lazania:int = 0;
  typewriter_piece1.addEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece1);
  typewriter_piece1.addEventListener(MouseEvent.MOUSE_UP, stop_drag_piece1);
  typewriter_piece2.addEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece2); 
  typewriter_piece2.addEventListener(MouseEvent.MOUSE_UP, stop_drag_piece2);
  typewriter_piece3.addEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece3);
  typewriter_piece3.addEventListener(MouseEvent.MOUSE_UP, stop_drag_piece3);
  typewriter_piece4.addEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece4);
  typewriter_piece4.addEventListener(MouseEvent.MOUSE_UP, stop_drag_piece4);
  typewriter_piece5.addEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece5);
  typewriter_piece5.addEventListener(MouseEvent.MOUSE_UP, stop_drag_piece5);
  typewriter_piece6.addEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece6);
  typewriter_piece6.addEventListener(MouseEvent.MOUSE_UP, stop_drag_piece6);
  stop();
  
  //typewriter piece 1 = K 
  function start_drag_piece1(event:MouseEvent):void{
  typewriter_piece1.startDrag();
  };
  function stop_drag_piece1(event:MouseEvent):void{
  if (Target1.hitTestObject(typewriter_piece1.Target1_Button)){
      typewriter_piece1.stopDrag();
      typewriter_piece1.x = Target1.x;
      typewriter_piece1.y = Target1.y;
      typewriter_piece1.mouseEnabled = false;
      typewriter_piece1.mouseChildren = false;
      lazania++;
      if(lazania == 6){
          typewriter_piece1.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece1);
          typewriter_piece1.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece1);
          typewriter_piece2.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece2);
          typewriter_piece2.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece2);
          typewriter_piece3.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece3);
          typewriter_piece3.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece3);
          typewriter_piece4.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece4);
          typewriter_piece4.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece4);
          typewriter_piece5.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece5);
          typewriter_piece5.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece5);
          typewriter_piece6.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece6);
          typewriter_piece6.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece6);
          gotoAndStop(1, "Scene 5");
      }
      //checklazania(lazania);
  }
  else{
      typewriter_piece1.x = 25;
      typewriter_piece1.y = 139,95;
      typewriter_piece1.stopDrag();
  }
  };
  
  //typewriter piece 2 = Y 
  function start_drag_piece2(event:MouseEvent):void{
  typewriter_piece2.startDrag();
  };
  function stop_drag_piece2(event:MouseEvent):void{
  if (Target2.hitTestObject(typewriter_piece2.Target2_Button)){
      typewriter_piece2.stopDrag();
      typewriter_piece2.x = Target2.x;
      typewriter_piece2.y = Target2.y;
      typewriter_piece2.mouseEnabled = false;
      typewriter_piece2.mouseChildren = false;
      lazania++;
      if(lazania == 6){
          typewriter_piece1.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece1);
          typewriter_piece1.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece1);
          typewriter_piece2.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece2);
          typewriter_piece2.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece2);
          typewriter_piece3.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece3);
          typewriter_piece3.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece3);
          typewriter_piece4.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece4);
          typewriter_piece4.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece4);
          typewriter_piece5.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece5);
          typewriter_piece5.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece5);
          typewriter_piece6.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece6);
          typewriter_piece6.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece6);
          gotoAndStop(1, "Scene 5");
      }
      //checklazania(lazania);
  
  }
  else{
      typewriter_piece2.x = 25;
      typewriter_piece2.y = 179,95;       
      typewriter_piece2.stopDrag();
  }
  };
  
  //typewriter piece 3 = Π
  function start_drag_piece3(event:MouseEvent):void{
  typewriter_piece3.startDrag()
  };
  function stop_drag_piece3(event:MouseEvent):void{
  if (Target3.hitTestObject(typewriter_piece3.Target3_Button)){
      typewriter_piece3.stopDrag();
      typewriter_piece3.x = Target3.x;
      typewriter_piece3.y = Target3.y;
      typewriter_piece3.mouseEnabled = false;
      typewriter_piece3.mouseChildren = false;
      lazania++;
      if(lazania == 6){
          typewriter_piece1.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece1);
          typewriter_piece1.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece1);
          typewriter_piece2.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece2);
          typewriter_piece2.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece2);
          typewriter_piece3.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece3);
          typewriter_piece3.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece3);
          typewriter_piece4.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece4);
          typewriter_piece4.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece4);
          typewriter_piece5.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece5);
          typewriter_piece5.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece5);
          typewriter_piece6.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece6);
          typewriter_piece6.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece6);
          gotoAndStop(1, "Scene 5");
      }
      //checklazania(lazania);
  }
  else{
      typewriter_piece3.x = 25;
      typewriter_piece3.y = 219,95;       
      typewriter_piece3.stopDrag();
  }
  };
  
  //typewriter piece 4 = P
  function start_drag_piece4(event:MouseEvent):void{
  typewriter_piece4.startDrag()
  };
  function stop_drag_piece4(event:MouseEvent):void{
  if (Target4.hitTestObject(typewriter_piece4.Target4_Button)){
      typewriter_piece4.stopDrag();
      typewriter_piece4.x = Target4.x;
      typewriter_piece4.y = Target4.y;
      typewriter_piece4.mouseEnabled = false;
      typewriter_piece4.mouseChildren = false;
      lazania++;
      if(lazania == 6){
          typewriter_piece1.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece1);
          typewriter_piece1.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece1);
          typewriter_piece2.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece2);
          typewriter_piece2.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece2);
          typewriter_piece3.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece3);
          typewriter_piece3.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece3);
          typewriter_piece4.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece4);
          typewriter_piece4.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece4);
          typewriter_piece5.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece5);
          typewriter_piece5.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece5);
          typewriter_piece6.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece6);
          typewriter_piece6.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece6);
          gotoAndStop(1, "Scene 5");
      }   
      //checklazania(lazania);
  }
  else{
      typewriter_piece4.x = 25;
      typewriter_piece4.y = 259,95;
      typewriter_piece4.stopDrag();
  }
  };
  
  //typewriter piece 5 = O
  function start_drag_piece5(event:MouseEvent):void{
  typewriter_piece5.startDrag()
  };
  function stop_drag_piece5(event:MouseEvent):void{
  if (Target5.hitTestObject(typewriter_piece5.Target5_Button)){
      typewriter_piece5.stopDrag();
      typewriter_piece5.x = Target5.x;
      typewriter_piece5.y = Target5.y;
      typewriter_piece5.mouseEnabled = false;
      typewriter_piece5.mouseChildren = false;
      lazania++;
      if(lazania == 6){
          typewriter_piece1.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece1);
          typewriter_piece1.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece1);
          typewriter_piece2.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece2);
          typewriter_piece2.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece2);
          typewriter_piece3.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece3);
          typewriter_piece3.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece3);
          typewriter_piece4.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece4);
          typewriter_piece4.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece4);
          typewriter_piece5.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece5);
          typewriter_piece5.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece5);
          typewriter_piece6.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece6);
          typewriter_piece6.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece6);
          gotoAndStop(1, "Scene 5");
      }
      //checklazania(lazania);
  }
  else{
      typewriter_piece5.x = 25;
      typewriter_piece5.y = 299,95;
  
      typewriter_piece5.stopDrag();
  }
  };
  
  //typewriter piece 6 = Σ
  function start_drag_piece6(event:MouseEvent):void{
  typewriter_piece6.startDrag()
  };
  function stop_drag_piece6(event:MouseEvent):void{
  if (Target6.hitTestObject(typewriter_piece6.Target6_Button)){
      typewriter_piece6.stopDrag();
      typewriter_piece6.x = Target6.x;
      typewriter_piece6.y = Target6.y;
      typewriter_piece6.mouseEnabled = false;
      typewriter_piece6.mouseChildren = false;
      lazania++;
      if(lazania == 6){
          typewriter_piece1.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece1);
          typewriter_piece1.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece1);
          typewriter_piece2.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece2);
          typewriter_piece2.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece2);
          typewriter_piece3.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece3);
          typewriter_piece3.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece3);
          typewriter_piece4.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece4);
          typewriter_piece4.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece4);
          typewriter_piece5.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece5);
          typewriter_piece5.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece5);
          typewriter_piece6.removeEventListener(MouseEvent.MOUSE_DOWN, start_drag_piece6);
          typewriter_piece6.removeEventListener(MouseEvent.MOUSE_UP, stop_drag_piece6);
          gotoAndStop(1, "Scene 5");
      }
      //checklazania(lazania);
  }
  else{
      typewriter_piece6.x = 25;
      typewriter_piece6.y = 339,95;
      typewriter_piece6.stopDrag();
  }
  };
  
  }
  </code></pre>