NaN and why?

1

heyall
I am creating a preloader for a an image that is drawn from an xml attribute linkage.
within the instance of the item being loaded there is an onEnterframe that contains this preloader.

  var tot = container.getBytesTotal();
        var load_bytes = container.getBytesLoaded();
var cont_loader:Number = ((load_bytes/tot )*100);
		_root.load_area.read_loader = cont_loader;

for a very brief moment before the preloader has began it displays NaN.

I am guessing that the onEnterFrame begins before the graphic is pulled into the swf file…

So does NaN stand for Nothing and Nowhere??