diff --git a/content.module b/content.module
index cfa7cda..763ee50 100644
--- a/content.module
+++ b/content.module
@@ -97,7 +97,7 @@ function content_menu() {
     foreach (node_get_types() as $type) {
       $type_name = $type->type;
       $content_type = content_types($type_name);
-      $type_url_str = $content_type['url_str'];
+      $type_url_str = isset($content_type['url_str']) ? $content_type['url_str'] : '';
       $items['admin/content/node-type/'. $type_url_str .'/fields'] = array(
         'title' => 'Manage fields',
         'page callback' => 'drupal_get_form',
diff --git a/modules/fieldgroup/fieldgroup.module b/modules/fieldgroup/fieldgroup.module
index 6b5b170..2fcd15c 100644
--- a/modules/fieldgroup/fieldgroup.module
+++ b/modules/fieldgroup/fieldgroup.module
@@ -39,7 +39,7 @@ function fieldgroup_menu() {
     foreach (node_get_types() as $type) {
       $type_name = $type->type;
       $content_type = content_types($type_name);
-      $type_url_str = $content_type['url_str'];
+      $type_url_str = isset($content_type['url_str']) ? $content_type['url_str'] : '';
       $items['admin/content/node-type/'. $type_url_str .'/groups/%'] = array(
         'title' => 'Edit group',
         'page callback' => 'drupal_get_form',