Fatal Error on WP Directory

Hi all,
I've just installed the directory plugin, set up a few test categories and now I've got some problems;

1. Every time I visit a category, this error message appears:
Fatal error: Call to undefined function dp_get_taxonomy_vars() in /wp-content/plugins/directory/themes/default/taxonomy.php on line 12

2. Some sub-categories don't appear on the main page

Can anyone help? The url of the directory is myashford[dot]com /business/