diff --git a/include/functions.inc.php b/include/functions.inc.php
index b0b396a0..535eede1 100644
--- a/include/functions.inc.php
+++ b/include/functions.inc.php
@@ -295,7 +295,7 @@ function serendipity_walkRecursive($ary, $child_name = 'id', $parent_name = 'par
     static $_resArray;
     static $_remain;
 
-    if (sizeof($ary) == 0) {
+    if (!is_array($ary) || sizeof($ary) == 0) {
         return array();
     }