As an as3 expert here are my ideas howyou could improve your code:
1) Use weakly referenced listeners.
use
Code:
loader.addEventListener(MouseEvent.CLICK, clickHandler, false, 0, true );
instead of
Code:
loader.addEventListener(MouseEvent.CLICK, clickHandler);
and for any other addEventListener.

2) Try to add this code:
// force immediate garbage collection - see grant skinner's article at
// http://www.gskinner.com/blog/archive...urce_ma_2.html
Code:
try {
				   new LocalConnection().connect('foo');
				   new LocalConnection().connect('foo');
} catch (e:*) {}
and see if the memory drops. You should better watch the memory, one load after another.

3) Remove event listeners on what you added: loader.addEventListener(MouseEvent.CLICK, clickHandler);