Index: nodereference_url.module
===================================================================
--- nodereference_url.module	(revision 59)
+++ nodereference_url.module	(working copy)
@@ -60,7 +60,7 @@
  * @param $node
  *   A fully loaded node object.
  * @param $teaser
- *   
+ *
  * @return
  *   An array of links for use with theme_links().
  */
@@ -180,7 +180,8 @@
   $field['widget']['node_link']['full'] = TRUE;
   if ($link = nodereference_url_build_link($node, $field)) {
     $options = array();
-    $options['attributes'] = $attributes + (array) $link['attributes'];
+    $link_attributes = (isset($link['attributes']))?(array) $link['attributes']: array();
+    $options['attributes'] = $attributes + $link_attributes;
     if ($link['query']) {
       $options['query'] = $link['query'];
     }