diff --git a/core/includes/install.inc b/core/includes/install.inc
index 533678f..9a5bf1d 100644
--- a/core/includes/install.inc
+++ b/core/includes/install.inc
@@ -1040,7 +1040,7 @@ function install_goto($path) {
  * @see drupal_requirements_url()
  */
 function drupal_current_script_url($query = array()) {
-  $uri = $_SERVER['SCRIPT_NAME'];
+  $uri = parse_url(request_uri(), PHP_URL_PATH);
   $query = array_merge(drupal_get_query_parameters(), $query);
   if (!empty($query)) {
     $uri .= '?' . drupal_http_build_query($query);