First AS3 file...ReferenceError: Error #1065: Variable draggableClip is not defined.

[SamuraiDave]

OK, this is my first attempt at coding in AS3.
I have created a class (within a package) and added it as the documentClass (within the stage properties in Flash CS3).

When I check the syntax of the code I get no errors, however, when I try to run the FLA file, I get the following error:

ReferenceError: Error #1065: Variable draggableClip is not defined.

Here is the code I am using:

package {

	import flash.display.MovieClip;
	import flash.events.MouseEvent;

	class draggableClip extends MovieClip {

		private var dragging:Boolean;

		public function draggableClip():void {
			dragging = false;
			this.addEventListener(MouseEvent.MOUSE_DOWN, thisMouseDown);
			this.addEventListener(MouseEvent.MOUSE_MOVE, thisMouseMove);
			this.addEventListener(MouseEvent.MOUSE_UP, thisMouseUp);
		}

		private function thisMouseDown(event: MouseEvent):void {
			trace("here i am at "+this);
			if (!this.dragging) {
				this.dragging = true;
				this.x = parent.mouseX;
				this.y = parent.mouseY;
			}
		}

		private function thisMouseMove(event: MouseEvent):void {
			if (this.dragging) {
				this.x = parent.mouseX;
				this.y = parent.mouseY;
			}
		}

		private function thisMouseUp(event: MouseEvent):void {
			this.dragging = false;
		}
	}
}

What I'm basically trying to do is attach (cast?) this class (if possible) to 3 MovieClip instances on stage. Am I going about this the wrong way?
I've been searching the internet for hours to try and get this FLA to compile successfully, so I'm hoping posting here will help.

Any help much appreceated,
Cheers,
SamuraiDave

[cancerinform]

public class draggableClip

Classes are by default internal.

[SamuraiDave]

Thanks very much for such a fast reply, that did the trick!