Showing Custom Post Types

I have recently created a custom post type using CustomPress, which worked great. However, I am now trying to show a list of these possts on my front page by using the Recent Custom Post Type Widget and I get the following error:
Fatal error: Call to undefined function preg_filter() in /home/busydaze/public_html/bb2/wp-content/plugins/recent-custom-post-type/recent-custom-post-type.php on line 191
Any idea what I have done wrong?