Fatal Error? Page is there, but will not show up/ Code

Hi All, recently a link starting giving this error when clicked on.I have gone into the folder and see the page. What do I change in the pages code? Help is very much appreciated!

Fatal error: Call to undefined function: c2c_get_recent_posts() in /home/sites/webhosting/opf/opf/www/wp-content/themes/opf/page_mmaria.php on line 16

This is the code of the page:

<?php
// page_mmaria.php - special index page for Mother Maria category
// OPF theme for WordPress by Ben de Groot

get_header();

if (have_posts()) : while (have_posts()) : the_post();
?>

<h2><?php opfHeading('St. Maria Skobtsova and those canonized with her'); ?></h2>

<h3>Resources available on the In Communion web site:</h3>
<ul>
<?php
// print a list of articles available on this website in this category
c2c_get_recent_posts ($num_posts = 100,
	$format = "<li>%post_URL%</li>",
	$categories = '9', // category ID of Mother Maria category
	$orderby = 'date',
	$order = 'ASC');
?>
</ul>

<?php
the_content(); // this is drawn from the 'static' WP page now
edit_post_link('Edit This', '<p class="editlink">', '</p>');

endwhile; endif;

get_footer();
?>