Error #1056 and Error #2007

[*]Error #1056: Cannot create property size on ResourceBox.
Line 16: var size:uint; // The size of the resource box currently
Line 86: var boxOpen:Tween = new Tween(this, “size”, Regular.easeInOut, 40, maxSize, 60);
I’m not sure why I’m getting this error as I did declare size.
If I make ResourceBox dynamic the error goes away, but I get:

[*]Error #2007: Parameter listener must be non-null.

var BoxOpenEvent:Function = BoxOpenEventHandler();
stage.addEventListener(MouseEvent.CLICK, BoxOpenEvent);
function BoxOpenEventHandler():Function {
  return function(e:TweenEvent):void {

According to

<a href=>this source</a> 

this should be fine.

Any help is appreciated. I’ve been stuck for hours =/