Easing, conflict with another code?

1

Hello, i want to move a movieclip to a certain position, i’m using voet’s code

MovieClip.prototype.easeX = function(to){
        this.onEnterFrame = function(){
                this._x = to-(to-this._x)/1.1;
                if(this._x > to-1 && this._x < to+1){
                        delete this.onEnterFrame
                        //do other stuff here, this is the point at which the object reaches its target
                }
        }
}
bt4.onRollOver = function(){
	pa.easeX(180.9);
}
bt4.onRollOut = function() {
	pa.easeX(-400);
}

but when i test it nothing happens. i also have this on the mc i want to move

onClipEvent (load){
_x=-400
}

I have another code on another frame with quite the same code but for a resizing, is it possible that there’s a conflict between it ?

Thanks,
Ubik