duplicateMovieClip Problem

1

I know it’s a general topic but I really have a problem with duplicating a movieClip. When I try to duplicate it, the code removes the old clip and generates a new one. So not duplicating. Here is the code:

function AddShape (cShape:String)
{
	S++;
	var Shapes:MovieClip = _root.MainStage.Shapes;
	var myShape = cShape.split("Thumb");
	var mcShape:MovieClip = myShape[1];
	
	_root.MainStage.Shapes.duplicateMovieClip("Shape"+S,_root.getNextHighestDepth());
	
	_root.MainStage["Shape"+S]._x += S*20;
	tellTarget(_root.MainStage["Shape"+S]){
		attachMovie("ShapeHolder","ShapeHolder",_root.getNextHighestDepth());
		ShapeHolder.attachMovie("Shape"+mcShape,"Shape",_root.getNextHighestDepth());
			
		onPress = function(){
			this.startDrag();
		}
		
		onRelease = onReleaseOutside = function(){
			this.stopDrag();
		}
	}
}