diff --git a/sites/all/modules/pathauto/pathauto.inc b/sites/all/modules/pathauto/pathauto.inc
index 42290ca..76c1c76 100644
--- a/sites/all/modules/pathauto/pathauto.inc
+++ b/sites/all/modules/pathauto/pathauto.inc
@@ -176,7 +176,7 @@ function pathauto_cleanstring($string, array $options = array()) {
   }
 
   // Empty strings do not need any proccessing.
-  if ($string === '' || $string === NULL) {
+  if ($string === '' || $string === NULL || ! is_string($string)) {
     return '';
   }