array_key_exists ERROR updating to GS 3.2.1

[D.O.]

For now, here is the core of the code...

PHP Code:

<div id="content">
<div class="content_item">

<div class='news'>Last News</div>
<?php $page='centerfold'; $data='pubDate'; ?>

<h1><?php getPageField($page,'title'); ?></h1>
<h2><?php getPageField($page,'metad'); ?></h2>
<?php getPageField($page,'content'); ?>

<?php include('boxes.inc.php'); ?>

<?php if (isset($_GET['post']) || "" ) { echo "<p class='copyright'>&copy; All rights reserved.</p>"; } ?>

</div><!--close content_item-->
</div><!--close content-->