diff --git a/hierarchical_select.js b/hierarchical_select.js
index 059fcc8..532faa1 100644
--- a/hierarchical_select.js
+++ b/hierarchical_select.js
@@ -558,7 +558,9 @@ Drupal.HierarchicalSelect.update = function(hsid, updateType, settings) {
       // for Hierarchical Select.
       for (var i in response) {
         if (response[i]['command'] && Drupal.ajax.prototype.commands[response[i]['command']]) {
-          Drupal.ajax.prototype.commands[response[i]['command']](this, response[i], status, hsid);
+          //pass "Drupal.ajax.prototype" instead of "this", which is "ajaxOptions", because 
+          //it does not have getEffect which is invoked upon it in ajax.js on line number 482
+          Drupal.ajax.prototype.commands[response[i]['command']](Drupal.ajax.prototype, response[i], status, hsid);
         }
       }