? system.patch
Index: modules/system.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/Attic/system.module,v
retrieving revision 1.320.2.15
diff -u -p -r1.320.2.15 system.module
--- modules/system.module	12 Dec 2006 21:49:13 -0000	1.320.2.15
+++ modules/system.module	21 Dec 2006 00:24:30 -0000
@@ -759,7 +759,7 @@ function system_theme_settings_submit($f
   $key = $values['var'];
 
   // Exclude unnecessary elements.
-  unset($values['var'], $values['submit'], $values['reset'], $values['form_id']);
+  unset($values['var'], $values['submit'], $values['reset'], $values['form_id'], $values['op'], $values['form_token']);
 
   if ($op == t('Reset to defaults')) {
     variable_del($key);