HELP: AS 2, UnloadMovie - Clips not removed

I’m building an actionscript based quiz, and have hit several walls along the way.
Most of them have since been knocked down, but one still puzzles me:
My actionscript generates buttons from an XML document ( which is imported into my AS classes ), and they are destroyed whenever one of them is clicked.
This cycle will regenerate the buttons with differing content until all questions have been answered.

For some strange reason, the buttons remain onstage after the last question has been answered, and I try to move on to my results pane.

Attached are the XML document ( for its structure ), the AS 2.0 classes I wrote, and the fla file.

The AS classes will need to be located in the same directory as the FLA file when test running it.

Any help is much appreciated!!