TypeError: Error #1010: A term is undefined and has no properties.

[nordberg60]

Please help, I'm an actionscript noob.

I have been getting the following error message with my code:
TypeError: Error #1010: A term is undefined and has no properties.

When I rollover the movieclip one or two the error occurs. Here is my code:

import fl.transitions.Tween;
import fl.transitions.easing.*;
import flash.display.DisplayObject;

var StateArray:Array = [one, two];

for (var i:int=0;i<2;i++)
{
StateArray[i].addEventListener( MouseEvent.ROLL_OUT, mouseCall );
StateArray[i].addEventListener( MouseEvent.ROLL_OVER, mouseCall );
StateArray[i].addEventListener( MouseEvent.CLICK, mouseCall );
StateArray[i].buttonMode = true;

trace(StateArray[i]);

function mouseCall( event:MouseEvent ):void
{

switch( event.type )
{
case MouseEvent.ROLL_OVER:
new Tween(StateArray[i], "scaleX", Strong.easeOut, StateArray[i].scaleX, 1.1, .50, true );
new Tween(StateArray[i], "scaleY", Strong.easeOut, StateArray[i].scaleY, 1.1, .50, true );
addChild(StateArray[i]);
break;

case MouseEvent.ROLL_OUT:
new Tween(StateArray[i], "scaleX", Strong.easeOut, StateArray[i].scaleX, 1.0, .50, true );
new Tween(StateArray[i], "scaleY", Strong.easeOut, StateArray[i].scaleY, 1.0, .50, true );
break;

case MouseEvent.CLICK :
//targetFrame = event.target.name;
removeChild(StateArray[i]);
gotoAndStop(2);
break;
}
}}

Any help would be greatly appreciated