diff --git a/modules/system/system.admin.inc b/modules/system/system.admin.inc
index 05543be..6129c4f 100644
--- a/modules/system/system.admin.inc
+++ b/modules/system/system.admin.inc
@@ -572,9 +572,10 @@ function system_theme_settings($form, &$form_state, $key = '') {
     // Process the theme and all its base themes.
     foreach ($theme_keys as $theme) {
       // Include the theme-settings.php file.
-      $filename = DRUPAL_ROOT . '/' . str_replace("/$theme.info", '', $themes[$theme]->filename) . '/theme-settings.php';
-      if (file_exists($filename)) {
-        require_once $filename;
+      $theme_settings_path = drupal_get_path('theme', $theme) . '/theme-settings.php';
+      if (file_exists(DRUPAL_ROOT . '/' . $theme_settings_path)) {
+        require_once DRUPAL_ROOT . '/' . $theme_settings_path;
+        $form_state['build_info']['files'][] = $theme_settings_path;
       }
 
       // Call theme-specific settings.