diff --git a/framework/base/helper.class.php b/framework/base/helper.class.php
index b159d9f0c3..f24311419d 100644
--- a/framework/base/helper.class.php
+++ b/framework/base/helper.class.php
@@ -557,7 +557,7 @@ class baseHelper
      */
     static public function isZeroDate($date)
     {
-        return substr($date, 0, 4) == '0000';
+        return (empty($date) or substr($date, 0, 4) == '0000');
     }
 
     /**