External .swf loaded into movieclip doesn't respond

Ok. I have a flash movie that contains a movieclip called “m_externalSection” and when a user presses a button it loads one of many external .swf’s.
These .swf files are basically filled with some buttons that move around when you click them and some text fields that change depending on what button you’ve clicked.

The external .swf files work fine on their own, but when you load them into “m_externalSection”, they don’t do anything, none of the buttons does anything at all. Flash ‘sees’ the buttons (the cursor changes to a hand) but when you click nothing happens.

What could I be doing wrong so that my external .swf isn’t working when it’s loaded into a movieclip?