newsportal_secondary_links() undefined

I've been using this excellent theme on a site I'm experimenting with.

I'm seeing this error message in the footer when secondary links are defined and configured. (See attached screen shot)

Fatal error: Call to undefined function: newsportal_secondary_links() in themes\newsportal\page.tpl.php on line 43

I see no definition of newsportal_secondary_links() in template.php, and yet it's being referenced from this theme's page.tpl.php.

From this theme's template.php file:

<div id="footer">
    <?php if (isset($secondary_links)) { ?><?php print newsportal_secondary_links() ?><br /><?php } ?>
    <?php print $footer_message ?>
  </div>

Where can I find the correct definition of newsportal_secondary_links()?