Drag and Drop Problem in Card Game

Question

Hi, everyone,
I'm trying to adapt the memory game in chapter 3 of the book "ActionScript 3.0 Game Programming University" for my own uses. I want to get all of the cards to flip and drag. I am able to flip the first card and drag it, but when I flip the second card over, I can't drag it. I have two files, MatchingGameMe.fla and MatchingGameMe.as. All of the actionscript is in MatchingGameMe.as. Here is the code. Does anyone see how I can modify it so that all the cards drag? Thanks in advance for your help!
MemoryGameMe.as:
package {
import flash.display.*;
import flash.events.*;
public class MatchingGameMe extends MovieClip {
  // game constants
  private static const boardWidth:uint = 6;
  private static const boardHeight:uint = 6;
  private static const boardOffsetX:Number = 120;
  private static const boardOffsetY:Number = 45;
  private var firstCard:Card;
  private var secondCard:Card;
  public function MatchingGameMe():void {
   // make a list of card numbers
   var cardlist:Array = new Array();
   for(var i:uint=0;i<boardWidth*boardHeight/2;i++) {
    cardlist.push(i);
    cardlist.push(i);
   // create all the cards, position them, and assign a randomcard face to each
   for(var x:uint=0;x<boardWidth;x++) { // horizontal
    for(var y:uint=0;y<boardHeight;y++) { // vertical
     var c:Card = new Card(); // copy the movie clip
     c.stop(); // stop on first frame
     var r:uint = Math.floor(Math.random()*cardlist.length); // get a random face
     c.cardface = cardlist[r]; // assign face to card
     cardlist.splice(r,1); // remove face from list
     c.addEventListener(MouseEvent.CLICK,clickCard); // have it listen for clicks
     addChild(c); // show the card
   // This function is called when the mouse button is pressed.
   function startDragging(event:MouseEvent):void
        c.startDrag();
    // This function is called when the mouse button is released.
    function stopDragging(event:MouseEvent):void
       c.stopDrag();
   c.addEventListener(MouseEvent.MOUSE_DOWN, startDragging);
   c.addEventListener(MouseEvent.MOUSE_UP, stopDragging);
  // player clicked on a card
  public function clickCard(event:MouseEvent) {
   var thisCard:Card = (event.target as Card); // what card?
    firstCard = thisCard; // note it
    firstCard.gotoAndStop(thisCard.cardface+2); // turn it over

Answer 1

Not sure if this will work inside classes, but in working with AS3, this would issue the command to object you just clicked, and the object you just dropped:
// This function is called when the mouse button is pressed.
   function startDragging(event:MouseEvent):void
        event.currentTarget.startDrag();
    // This function is called when the mouse button is released.
    function stopDragging(event:MouseEvent):void
       event.currentTarget.stopDrag();