1119: Access of possibly undefined property (easy to fix) Really need help :(

programming flash
1

Hey guys and gals, just wondering if anyone can help with this problem. I think it will be extremely easy for most of you, I really need help tho as I am a noob to as3

My code is as follows

buttons_mc.vespabutton1_btn.addEventListener(MouseEvent.CLICK,vespabutton1Click);

function vespabutton1Click(e:MouseEvent):void {
    trace("click1");
    root.vespaArray_mc.x = 175;
    root.vespaArray_mc.y = -51;
}

buttons_mc.vespabutton2_btn.addEventListener(MouseEvent.CLICK,vespabutton2Click);

function vespabutton2Click(e:MouseEvent):void {
    trace("click2");
    root.vespaArray_mc.x = -759;
    root.vespaArray_mc.y = -51;
}

and the error i get is as follows:

1119: Access of possibly undefined property vespaArray_mc through a reference with static type flash.displayisplayObject.

I have attached my working file, maybe useful

Any help on this problem will be greatly appreciated.

Thanks in advance

Ryan