diff --git includes/bootstrap.inc includes/bootstrap.inc
index be0a471..892c735 100644
--- includes/bootstrap.inc
+++ includes/bootstrap.inc
@@ -677,7 +677,7 @@ function drupal_get_filename($type, $name, $filename = NULL) {
     try {
       if (function_exists('db_query')) {
         $file = db_query("SELECT filename FROM {system} WHERE name = :name AND type = :type", array(':name' => $name, ':type' => $type))->fetchField();
-        if (file_exists(DRUPAL_ROOT . '/' . $file)) {
+        if ($file && file_exists(DRUPAL_ROOT . '/' . $file)) {
           $files[$type][$name] = $file;
         }
       }