--- modules/file/file.module	2010-12-29 04:35:23.000000000 +0100
+++ modules/file/file1.module	2011-04-01 15:28:05.000000000 +0200
@@ -143,9 +143,12 @@ function file_file_download($uri, $field
   // Find out which (if any) fields of this type contain the file.
   $references = file_get_file_references($file, NULL, FIELD_LOAD_CURRENT, $field_type);
 
-  // If there are no references, stop processing, to avoid returning headers
+  // If there are no references, or the user doesn't have access to the corresponding 
+  // entity(ies) where the file is attached to (in wich case, an array of empty 
+  // values is returned), stop processing, to avoid returning headers
   // for files controlled by other modules.
-  if (empty($references)) {
+  $empty = array_filter($references);
+  if (empty($references) || (empty($empty))) {
     return;
   }