MC property not found?

programming flash
1

I have a movie clip that has a property doSelect().

I add the movie clip thus:

var obj:MovieClip = new Square();
addChild(obj);
obj.addEventListener(MouseEvent.CLICK, objClickListener);

function objClickListener(me:MouseEvent):void {
	me.target.doSelect();
}

This works as expected when I click the instance.

HOWEVER, when I add several instances of my movie clip thus:

for (var i:int=1; i<10; i++) {
	var obj:MovieClip = new Square();
	addChild(obj);
	obj.x = Math.random()*(stage.stageWidth - obj.width);
	obj.y = Math.random()*(stage.stageHeight - obj.height);
	obj.addEventListener(MouseEvent.CLICK, objClickListener);
}

function objClickListener(me:MouseEvent):void {
	me.target.doSelect();
}

…clicking any one of the instances produces the following error:

[FONT=“Courier New”]ReferenceError: Error #1069: Property doSelect not found on flash.display.Sprite and there is no default value.
at myFile_fla::MainTimeline/objClickListener()[/FONT]

What am I doing wrong?