Index: devel.module
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/devel/devel.module,v
retrieving revision 1.437
diff -u -p -r1.437 devel.module
--- devel.module	11 Sep 2010 22:27:28 -0000	1.437
+++ devel.module	13 Sep 2010 03:48:36 -0000
@@ -508,7 +508,7 @@ function devel_silent() {
   // Don't interfere with private files/images.
   return
     function_exists('drupal_is_cli') && drupal_is_cli() ||
-    strpos($_SERVER['HTTP_USER_AGENT'], 'ApacheBench') !== FALSE ||
+    (!isset($_SERVER['HTTP_USER_AGENT'] || strpos($_SERVER['HTTP_USER_AGENT'], 'ApacheBench') !== FALSE) ||
     !empty($_REQUEST['XDEBUG_PROFILE']) ||
     isset($GLOBALS['devel_shutdown']) ||
     strstr($_SERVER['PHP_SELF'], 'update.php') ||