removeChild errors

I am trying to create a movie clip by using a button in Flash. The button’s instance is cir_btn which creates a circle on the stage

I am using an external .as file to generate the public class Cir which calls upon several mouse actions as well as referrence a movie clip in my library that contains a shape. The movie clip’s name is circle and it has a linkage of circle

I am able to repeatedly generate circles inside of the swf, however when I try to use the remove button, this is what I get:

ReferenceError: Error #1065: Variable circ is not defined.
at Cir/::removeCirc()

Here is the code for my .as file:

package {
import flash.display.MovieClip;
import flash.events.MouseEvent;
public class Cir extends MovieClip {

var timeline:MovieClip;
public function Cir(tl:MovieClip) {

timeline=tl;
timeline.cir_btn.addEventListener(MouseEvent.MOUSE_DOWN, onMouseDown);
timeline.reset_btn.addEventListener(MouseEvent.MOUSE_DOWN, removeCirc);

}

public function onMouseDown( event:MouseEvent ):void
{
var circ:MovieClip = new circle;
circ.x = 110;
circ.y = 70;
this.addChild(circ);

}
private function clicked(e:MouseEvent):void {
removeEventListener(MouseEvent.CLICK,clicked);
}

private function removeCirc( event:MouseEvent ):void {
parent.removeChild(circ);
}
}

}

Just to see if I was ever meeting the removeCirc function, I did both a trace and I changed the code from parent.removeChild(circ); to parent.removeChild(this); which does remove the circle from the stage, but I can’t generate a new circle as long as I have the swf open. I am having a very hard time unlearning AS2 to learn AS3. Can any one help me out?

EXTRA CREDIT: I am also looking for a way to constrain the circle movie clip to a certain portion of the stage only. Some kind of bounds command so that the movie clip will only display in a rectangular area inside of the swf. This is not as important right now as figuring out how to remove the circle, but I will need to get to it eventually.

Thanks in advance.