? 518512.patch
? modules/search/518512.patch
? sites/default/files
? sites/default/private
? sites/default/settings.php
Index: modules/search/search.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/search/search.module,v
retrieving revision 1.344
diff -u -p -r1.344 search.module
--- modules/search/search.module	11 Apr 2010 18:54:11 -0000	1.344
+++ modules/search/search.module	20 Apr 2010 04:36:54 -0000
@@ -953,6 +953,10 @@ function search_box_form_submit($form, &
     unset($_GET['destination']);
   }
 
+  if ($form_state['values']['search_block_form'] == '') {
+    form_set_error('keys', t('Please enter some keywords.'));
+  }
+
   $form_id = $form['form_id']['#value'];
   $form_state['redirect'] = 'search/node/' . trim($form_state['values'][$form_id]);
 }