diff --git a/webform_conditional.module b/webform_conditional.module
index 562a4da..d306c9a 100644
--- a/webform_conditional.module
+++ b/webform_conditional.module
@@ -295,11 +295,13 @@ function _webform_conditional_get_submitted_values($form_state) {
   //get components that are on the current page
   if (!empty($form_state['values']['details']['page_num'])) {
     $page_num = $form_state['values']['details']['page_num'];
-    if ($form_state['clicked_button']['#id'] == 'edit-previous') {
-      $page_num--;
-    }
-    elseif ($form_state['clicked_button']['#id'] == 'edit-next') {
-      $page_num++;
+    if (isset($form_state['clicked_button'])) {
+      if ($form_state['clicked_button']['#id'] == 'edit-previous') {
+        $page_num--;
+      }
+      elseif ($form_state['clicked_button']['#id'] == 'edit-next') {
+        $page_num++;
+      }
     }
     $tree = _webform_conditional_get_page_tree($tree, $page_num);
   }