Moving a Class into a Movie Clip? Error #2007

[ScriptAction]

I've just started learning about classes and Flash in general.

I created a little Flash file that used classes and all was working well.

But then I decided I wanted to move all of what I'd done on the main timeline into a Movie Clip. Now most things don't work.

I'm guessing that the things in the class were 'linking' or 'referring' to things on the main scene 1 stage which are now in a movie clip.

I've tried to fix it but haven't had any luck. I'm getting errors like:

TypeError: Error #2007: Parameter hitTestObject must be non-null.
at flash.display:isplayObject/_hitTest()
at flash.display:isplayObject/hitTestObject()
at DragDrop/drop()

I'm uploading the two class files and the fla file for a clearer picture of what is happening. I'll also upload the working versions before I moved it into a movie clip.

I've moved it into a movie clip as I want to have the same pieces of action happening multiple times and guessed this was the best way... Is it?

Thanks for your time.

draganddrop - working.fladraganddrop.fla

Can we not upload class files? Here they are:
https://dl.dropbox.com/u/309502/flash/flash.rar

Map class file:

package 
{

	import flash.display.*;
	import flash.events.*;
	

	public class Map extends MovieClip
	{
		var dragdrops:Array;
		var numOfMatches:uint = 0;
		var speed:Number = 25;

		public function Map()
		{
			//constructor code
			dragdrops = [red1,blue1,blue2,yellow1,green1];
			var currentObject:DragDrop;
			for(var i:uint = 0; i < dragdrops.length; i++)
			{
				currentObject = dragdrops[i];
				currentObject.target = getChildByName(currentObject.name + "_target");
			}
			
		}
		
		public function match():void
		{
			numOfMatches++;
			if(numOfMatches == dragdrops.length)
			{
				win.addEventListener(Event.ENTER_FRAME, winGame);
			}
		}
		function winGame(event:Event):void
		{
			win.y -= speed;
			
			if(win.y <= 0)
			{
				win.y = 0;
				win.removeEventListener(Event.ENTER_FRAME, winGame);
				win.addEventListener(MouseEvent.CLICK, clickWin);
			}
		}
		
		function clickWin(event:MouseEvent):void
		{
			win.removeEventListener(MouseEvent.CLICK, clickWin);
			win.addEventListener(Event.ENTER_FRAME, animateDown);
			
			var currentObject:DragDrop;
			for(var i:uint = 0; i < dragdrops.length; i++)
			{
				currentObject = dragdrops[i];
				//getChildByName(currentObject.name + "_target").alpha = 0;
				
				currentObject.visible = true;
			}
			numOfMatches = 0;
			addChild(win);
			
			
		}
		function animateDown(event:Event):void
		{
			win.y += speed;
			
			if(win.y >= stage.stageHeight)
			{
				win.y = stage.stageHeight;
				win.removeEventListener(Event.ENTER_FRAME, animateDown);
			}
		}
	}

}

DragDrop class file:

package 
{
	import flash.display.*;
	import flash.events.*;
	
	public class DragDrop extends Sprite
	{
		var origX:Number;
		var origY:Number;
		var target:DisplayObject;

		public function DragDrop()
		{
			// constructor code
			//origX = x;
			//origY = y;
			addEventListener(MouseEvent.MOUSE_DOWN, drag);
			buttonMode = true;
		}
		
		function drag(evt:MouseEvent):void
		{
			stage.addEventListener(MouseEvent.MOUSE_UP, drop);
			startDrag();
			parent.addChild(this);
		}
		function drop(evt:MouseEvent):void
		{
			stage.removeEventListener(MouseEvent.MOUSE_UP, drop);
			stopDrag();
			
			if(hitTestObject(target))
			{
				visible = false;
				//target.alpha = 1;
				Object(parent).match();
			}
			
			//x = origX;
			//y = origY;
		
		}
			
	}

}

Thanks again.

[cancerinform]

target is null. Replace "target" with "this" and it works. Also change Object(parent).match(); to Object(parent).match;
since match is not a function.

[ScriptAction]

Thanks but I'm now getting this error:
Map.as, Line 22 1084: Syntax error: expecting identifier before this.
For this line: currentObject.this = getChildByName(currentObject.name + "_target");

[cancerinform]

Make the changes only in DragDrop.as but not in Map.as.

[ScriptAction]

Ok, have done that. Now getting this error:
DragDrop.as, Line 10 1084: Syntax error: expecting identifier before this.

Line 10: var thisisplayObject;

And also these errors:

Map.as, Line 1 5000: The class 'Map' must subclass 'flash.display.MovieClip' since it is linked to a library symbol of that type.
DragDrop.as, Line 1 5000: The class 'DragDrop' must subclass 'flash.display.MovieClip' since it is linked to a library symbol of that type.
DragDrop.as, Line 1 5000: The class 'DragDrop' must subclass 'flash.display.MovieClip' since it is linked to a library symbol of that type.
DragDrop.as, Line 1 5000: The class 'DragDrop' must subclass 'flash.display.MovieClip' since it is linked to a library symbol of that type.
DragDrop.as, Line 1 5000: The class 'DragDrop' must subclass 'flash.display.MovieClip' since it is linked to a library symbol of that type.

Nothing is dragable either!

Thanks.

[cancerinform]

Just get back to the original class and then change
if(hitTestObject(target))
to
if(hitTestObject(this))
You can delete the line var targetisplayObject;
That line was nonsense from the beginning, because target was not defined in that class. That is why it gave null.

[ScriptAction]

Thanks! Now I'm getting these errors:

C:\Users\Joe\Documents\Flash\Map.as, Line 17 1120: Access of undefined property red1.
C:\Users\Joe\Documents\Flash\Map.as, Line 17 1120: Access of undefined property blue1.
C:\Users\Joe\Documents\Flash\Map.as, Line 17 1120: Access of undefined property blue2.
C:\Users\Joe\Documents\Flash\Map.as, Line 17 1120: Access of undefined property yellow1.
C:\Users\Joe\Documents\Flash\Map.as, Line 17 1120: Access of undefined property green1.
C:\Users\Joe\Documents\Flash\Map.as, Line 22 1119: Access of possibly undefined property target through a reference with static type DragDrop.

Line 17: buttonMode = true;

Line 22: stage.addEventListener(MouseEvent.MOUSE_UP, drop);

Thanks