お絵描きソフトを作りたいのですが、どこが悪いのか、わからずに、つまずいています。
コードは、以下のようです。
わかる方、教えてください。

コード

package {

import flash.display.Graphics;
import flash.display.Sprite;
import flash.events.MouseEvent;
import flash.geom.Point;

public class draw_lines_001 extends Sprite {

private var clicked:Boolean=false;
private var sprite:Sprite=new Sprite();
private var g:Graphics=sprite.graphics;

public function draw_lines_001():void {
draw();
}

private function draw():void{
addEventListener(MouseEvent.MOUSE_DOWN,mouse_down);
addEventListener(MouseEvent.MOUSE_MOVE,mouse_move);
addEventListener(MouseEvent.MOUSE_UP,mouse_up);
// addEventListener(Event.ENTER_FRAME,enter_frame);
}

private function mouse_down(e:MouseEvent):void{
clicked=true;
var point_global:Point=new Point(stage.mouseX,stage.mouseY);
var point_local:Point=sprite.globalToLocal(point_global);
g.moveTo(point_local.x,point_local.y);
}

private function mouse_move(e:MouseEvent):void{
if(clicked){
var point_global:Point=new Point(stage.mouseX,stage.mouseY);
var point_local:Point=sprite.globalToLocal(point_global);
g.lineStyle(5,0xffcccc,0.1);
g.lineTo(point_local.x,point_local.y);
stage.addChild(sprite);
sprite.x=200;
sprite.y=200;
}
}

private function mouse_up(e:MouseEvent):void{
clicked=false;
}
}
}