diff -urp --strip-trailing-cr ../drupal-6.x-dev/modules/system/system.admin.inc ./modules/system/system.admin.inc
--- ../drupal-6.x-dev/modules/system/system.admin.inc	2007-12-08 15:06:22.000000000 +0100
+++ ./modules/system/system.admin.inc	2007-12-11 23:50:35.000000000 +0100
@@ -513,18 +513,17 @@ function system_theme_settings(&$form_st
 }
 
 function system_theme_settings_submit($form, &$form_state) {
-  $op = isset($_POST['op']) ? $_POST['op'] : '';
-  $key = $form_state['values']['var'];
+  $values = $form_state['values'];
+  $key = $values['var'];
 
-  // Exclude unnecessary elements.
-  unset($form_state['values']['var'], $form_state['values']['submit'], $form_state['values']['reset'], $form_state['values']['form_id']);
-
-  if ($op == t('Reset to defaults')) {
+  if ($values['op'] == t('Reset to defaults')) {
     variable_del($key);
     drupal_set_message(t('The configuration options have been reset to their default values.'));
   }
   else {
-    variable_set($key, $form_state['values']);
+    // Exclude unnecessary elements before saving.
+    unset($values['var'], $values['submit'], $values['reset'], $values['form_id'], $values['op'], $values['form_build_id'], $values['form_token']);
+    variable_set($key, $values);
     drupal_set_message(t('The configuration options have been saved.'));
   }