Yes, the problem was that the form method was set to get, not post.
The code used the GET method, because that was what the form was set to. Once the forms method was changed to POST, the code needed to be changed as well.
The other problem was a common php problem where it will loose site of session values.
Adding this code to the top of the page:
<?php if(!session_id()) session_start(); ?>
forces PHP to look for the session values.
Kathi, are you still having problems? Or where you able to work through the issue?