--- webform_encrypt.module	2012-03-26 16:34:29.377297200 +0800
+++ webform_encrypt.module	2012-03-26 16:35:06.386123100 +0800
@@ -63,8 +63,10 @@
  * Save encryption settings for a component.
  */
 function webform_encrypt_webform_component_presave(&$component) {
-  $component['extra'] = array_merge($component['extra'], $component['encryption']);
-  unset($component['encryption']);
+  if (!empty($component['encryption'])) {
+    $component['extra'] = array_merge($component['extra'], $component['encryption']);
+    unset($component['encryption']);
+  }
 }
 
 /**