hook_menu is incorrect.

This code is incorrect:

    // User admin callback.
  $any = count(_taxonomy_delegate_my_vocabularies());
  if ($any) {
    $items['category_admin'] = array(
      'title' => '@name',
      'title arguments' => array('@name' => variable_get('taxonomy_delegate_menu', t('Administer My Categories'))),
      'page callback' => 'taxonomy_delegate_mycategories',
      'access arguments' => array('access content'),
      );
  }

This code will not work on various sites. For instance, this not work on my site. Absolutely all users see 404 error.
There must used custom access callback function. See http://drupal.org/node/109157