[Neirol]

В FLA:

var mh:MouseHunter = new MouseHunter();
addChild(mh);

В MouseHunter.as:

package {
	import flash.display.Sprite;
	import flash.display.Graphics;
 
	public class MouseHunter extends Sprite
	{
		private const a:Number = 0.2;
		public function MouseHunter() 
		{
			graphics.beginFill(0);
			graphics.drawOval(0, 0, 20);
			addEventListener(Event.ENTER_FRAME, onEnterFrameHandler);
		}
 
		public function onEnterFrameHandler(e:Event):void 
		{
			x += a * mouseX;
			y += a * mouseY;
		}
	}
}

Результат: пустое окно, ошибка - 1046: Type was not found or was not a compile-time constant: Event. - 15 строка.