Mc's timeline move on drop?

I’m trying to create a small movie where users drag a button and drops it on a MC. If a drop is successful, another MC’s timeline moves one frame each time the drop is successful. If all drops are successful then the root goes to the “success” frame (which I’ve managed to do…thanks mate for that!). How could I modify my script to enable me to do that, please?

This is the code I’m using for the drag and ease section:

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 {
        dropped++ // delcare this at the beginig to as dropped = 0 
        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;
                if(dropped == buttons.length)
                gotoAndPlay ("success");
                //  <-----------------
            }
        };
    }
}

wB