How to remove a tween before moving to next frame in as3 - actionscript-3

Question

I have a movieclip which spins. I want it when users drag and drop it to stop spinning and be in it's initial position. I wrote this code but i get error TypeError: Error #1009: Cannot access a property or method of a null object reference.
at omoixes10_fla::MainTimeline/EntFrame() when I move to next frame. I can not see what i did wrong. Can you please help me with my code? Do I have to remove tween before I move to next frame?
import flash.display.MovieClip;
import fl.transitions.Tween;
import fl.transitions.easing.*;
tick1.parent.removeChild(tick1);
wrong1.parent.removeChild(wrong1);
sentences2.buttonMode=true;
sentences1.buttonMode=true;
Piece1_mc.buttonMode=true;
var my_x:int=stage.stageWidth
var my_y:int=stage.stageHeight
var myWidth:int=0-my_x;
var myHeight:int=0-my_y;
var boundArea:Rectangle=new Rectangle(my_x, my_y, myWidth ,myHeight);
var spin:Tween=new Tween(Piece1_mc, "rotation",Elastic.easeInOut,0,360,5,true);
spin.stop();
sentences2.addEventListener(MouseEvent.CLICK, fl_MouseClickHandler);
function fl_MouseClickHandler(event:MouseEvent):void
{
snoopy.gotoAndPlay(2);
addChild(tick1);
addChild(wrong1);
sentences2.removeEventListener(MouseEvent.CLICK, fl_MouseClickHandler);
sentences1.removeEventListener(MouseEvent.CLICK, fl_MouseClickHandler_2);
spin.start();
spin.addEventListener(TweenEvent.MOTION_FINISH, onFinish);
function onFinish(e:TweenEvent):void {
e.target.yoyo();
{
Piece1_mc.addEventListener(MouseEvent.MOUSE_DOWN, DragP1);
function DragP1 (event:MouseEvent):void
{
Piece1_mc.startDrag();
Piece1_mc.startDrag(false,boundArea);
spin.stop();
}
stage.addEventListener(MouseEvent.MOUSE_UP, DropP1);
function DropP1(event:MouseEvent):void
{
Piece1_mc.stopDrag();
}
if(Targ1_mc.hitTestObject(Piece1_mc.Tar1_mc)) {
Piece1_mc.x=677;
Piece1_mc.y=48,10;
myTimer.start();
spin.stop();
}
}
}
sentences1.addEventListener(MouseEvent.CLICK, fl_MouseClickHandler_2);
function fl_MouseClickHandler_2(event:MouseEvent):void
{
snoopy.gotoAndPlay(64);
}
var myTimer:Timer = new Timer(2000,1);
myTimer.addEventListener(TimerEvent.TIMER, timerListener);
function timerListener (e:TimerEvent):void {
gotoAndStop(15);
if (Piece1_mc.parent)
{
Piece1_mc.parent.removeChild(Piece1_mc);
}if (tick1.parent)
{
tick1.parent.removeChild(tick1);
}
if (wrong1.parent)
{
wrong1.parent.removeChild(wrong1);
}
}
}

Answer 1

So the first problem was adding your event listeners inside an enter frame which was not the right way to do since it will keep on adding event listeners at every frame.
Second, you should use a mouse move event listener as I've recommended before to track and test your hit test.
Thirdly, since you are rotating your MovieClip, and you want it to go back to its initial state, you should do :
Piece1_mc.rotation=0;
Hope this helps.