I dont see on the results page where you have added code to set the sessions.
near line 1, you should code like this to set the session for the Center_Name element:
$_SESSION['Center_Name'] = $_GET['Center_Name'];
then in the body you can use this code to show the center name search term:
<?php echo(isset($_SESSION['Center_Name'])?"Center Name: ".$_SESSION['Center_Name']:""); ?>
repeat that for each of the form elements.
NOTE: Instead of saving the pages as text, compress the original php pages to a zip archive to send the php pages.