Index: includes/common.inc
===================================================================
--- includes/common.inc	(revision )
+++ includes/common.inc	(revision )
@@ -1898,7 +1898,9 @@
     if ($is_writable && $preprocess_css) {
       // Prefix filename to prevent blocking by firewalls which reject files
       // starting with "ad*".
-      $filename = 'css_'. md5(serialize($types) . $query_string) .'.css';
+      $sorted_types = $types;
+      ksort($sorted_types);
+      $filename = 'css_'. md5(serialize($sorted_types) . $query_string) .'.css';
       $preprocess_file = drupal_build_css_cache($types, $filename);
       $output .= '<link type="text/css" rel="stylesheet" media="'. $media .'" href="'. base_path() . $preprocess_file .'" />'."\n";
     }
@@ -2301,7 +2303,9 @@
   if ($is_writable && $preprocess_js && count($files) > 0) {
     // Prefix filename to prevent blocking by firewalls which reject files
     // starting with "ad*".
-    $filename = 'js_'. md5(serialize($files) . $query_string) .'.js';
+    $sorted_files = $files;
+    ksort($sorted_files);
+    $filename = 'js_'. md5(serialize($sorted_files) . $query_string) .'.js';
     $preprocess_file = drupal_build_js_cache($files, $filename);
     $preprocessed .= '<script type="text/javascript" src="'. base_path() . $preprocess_file .'"></script>'."\n";
   }