1. a MC called content, full size as the movie, act as a blank platform to load external swf
2. another MC button containing a button, click to loadMovie, placed on top of MC content
I'd like to click the button in button to load an external swf in content.
IMHO...your problem stems from putting CODE on the actual 'button' inside the movieClip..
you should out 'all' code in the MAIN timeline.. on the FRAME.. not on any objects/movieClips.
when you put code ON an object.movieClip.. you need to be VERY clear and understand what your scope is so you can path to other variables/data & code..
when you place code ON an object.. and use of THIS means the object that has the code poasted to it..
so you needed to navigate form that time line to the MAIN (_parent) time line to find your CONTENT movieClip.. and load your contents there..