ActionScript 3.0 :: AddChild To Loaded SWF From Its Library

I get

ActionScript Code:
TypeError: Error #1007: Instantiation attempted on a non-constructor.
at com::index/openWindow()

My mainContainer.swf loads in index.swf, within index.swf I have a movieclip in my library named page_mc that exports with it.

I want to add page_mc to the index.swf stage from a AS file that I import within my document class of mainContainer.

ActionScript Code:
public function openWindow(e:Event)
{
var page_mc = new page_mc();
path.addChild(page_mc);
}