Tween works...just not on flash 8?

1

Hi I have this tween prototype, it works but not if I compile for flash 8. Any ideas?? Actually, it kind of works, its really just the scale bit that isn’t…

import mx.transitions.Tween;
import mx.transitions.easing.*;
//my tween prototype //////////
MovieClip.prototype.easeInOut = function(endxscale, endyscale, endX, endY,startxrotation, endxrotation, secs, easeType) {
   // var easeType = Regular.easeInOut;
    var startX = this._x;
    var startY = this._y; 
    var startXscale = this._xscale;
    var startYscale = this._yscale;  
   
    if (this.xTween == undefined) {
        this.xTween = new Tween(this, "_x", easeType, startX, endX, secs, true);
        this.yTween = new Tween(this, "_y", easeType, startY, endY, secs, true);
        this.xscaleTween = new Tween(this, "_xscale", easeType, startXscale, endXscale, secs, true);
        this.yscaleTween = new Tween(this, "_yscale", easeType, startYscale, endYscale, secs, true);
        this.xrotation = new Tween(this, "_rotation", easeType, startxrotation, endxrotation, secs, true);
    } else {
        this.xTween.continueTo(endX, secs);
        this.yTween.continueTo(endY, secs);
        this.xscaleTween.continueTo(endXscale, secs);
        this.yscaleTween.continueTo(endYscale, secs);
        this.xrotation.continueTo(endxrotation, secs);
        
    }
};