Loaded swf issue

I have a loaded SWF into a simple “holder” empty movieclip I have on the root stage. Inside that SWF I have two variables that have “stage.stageHeight” and “stage.stageWidth” in them. If I leave them on the code and test the root movie I get this error:

TypeError: Error #1009: Cannot access a property or method of a null object reference.

So basically I can’t seem to get the variables to get the parent stage. Anyway to get around that?
Thanks in advance,