--- includes/file.inc	2008-10-30 17:35:56.000000000 +0100
+++ includes/file_new.inc	2008-11-27 17:13:28.000000000 +0100
@@ -260,7 +260,7 @@ function file_check_location($source, $d
     $source = realpath(dirname($source)) . '/' . basename($source);
   }
   $directory = realpath($directory);
-  if ($directory && strpos($source, $directory) !== 0) {
+  if (!is_dir($directory) || strpos($source, $directory) !== 0) {
     return FALSE;
   }
   return $source;