Get total frames of externally loaded SWF

I have a bunch of AS2 swfs that I am loading into an AS3 project. These AS2 swfs are powerpoint slides essentially. In my onComplete method, I trace( and I get this error:

ReferenceError: Error #1069: Property totalFrames not found on flash.display.AVM1Movie and there is no default value.
	at Index/::displaySlide()

How can I get the total frames of the SWF in AS3 on an AS2 movie?

…or alternatively find out when the swf is done playing?