gotoAndPlay ("won't work"); Why not?

I’m using the code below and I want the timeline to move to a new frame when all the drags have been completed correctly but I’m not sure where to add the gotoAndPlay script. Suggestions anyone?


stop();
displayTime = 40; 
      countDown = function(message){
  
          displayTime--; 
          if (displayTime == 0){
  
              clearInterval(timer); 
              gotoAndPlay ("TimesUp");
  
          }
  
      } 
      timer = setInterval(countDown, 1000); 
    
    

    
var buttons:Array = [button1, button2, button3, button4, button5, button6, button7];
var sections:Array = ["J'ai- correct!", "Tu as- correct", "Correct", "Ils ont - correct!", "Elles ont - correct!", "Nous avons - correct!", "Vous avez - correct!"];
var speed:Number = .1;
showNames.text = "Let's Go!";
//  <-----------------
for (i=0; i<buttons.length; i++) {
    buttons*.startX = buttons*._x;
    buttons*.startY = buttons*._y;
    buttons*.onPress = dragButton;
    buttons*.onRelease = buttons*.onReleaseOutside=easeBack;
    buttons*.buttonName = sections*;
    buttons*.id = (i+1); // <- add this to store the number at the end of the dropZone mc's
    //  <-----------------
}
function dragButton():Void {
    delete this.onEnterFrame;
    this.startDrag();
}
function easeBack():Void {
    this.stopDrag();
    trace(this);
    var dropZone:MovieClip = _root["dropZone"+this.id]; // <- add this to know which movie clip
    if (!dropZone.hitTest(this)) {
        this.onEnterFrame = function() {
            this._x += (this.startX-this._x)*speed;
            this._y += (this.startY-this._y)*speed;
if (this._x<this.startX+1 && this._x>this.startX-1 && this._y<this.startY+1 && this._y>this.startY-1) {
                this._x = this.startX;
                this._y = this.startY;
                delete this.onEnterFrame;
                }
        };
    } else {
        this.onEnterFrame = function() {
            this._x += (dropZone._x-this._x)*speed;
            this._y += (dropZone._y-this._y)*speed;
if (this._x<dropZone._x+1 && this._x>dropZone._x-1 && this._y<dropZone._y+1 && this._y>dropZone._y-1) {
                this._x = dropZone._x;
                this._y = dropZone._y;
                delete this.onEnterFrame;
                showNames.text = this.buttonName;
                //  <-----------------
            }
        };
    }
}

Thanks a bunch!

Yossi