Help Flex Problem

Hi i have just downloaded Flex Builder 2 and Flash 9 player for Internet Explorer. I added this piece of code in my file:

[LEFT] package {
	import flash.display.Sprite;

	public class ProgrammingBasics extends Sprite
		public function ProgrammingBasics()
			var quantity:Number = 9;

However, when i clicked on the debug button i get this messag;

Failed to connect; session timed out.
Ensure that:

  1. You compiled your Flash application with debugging on.
  2. You are running the debug version of the Flash Player.

I downloaded Flex builder 2 but is there anything i need to do, PLEASE HELP GUYS.