Index: modules/system/system.admin.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/system/system.admin.inc,v
retrieving revision 1.23
diff -u -p -r1.23 system.admin.inc
--- modules/system/system.admin.inc	9 Nov 2007 19:16:22 -0000	1.23
+++ modules/system/system.admin.inc	12 Nov 2007 02:18:32 -0000
@@ -1144,6 +1144,14 @@ function system_error_reporting_settings
     '#description' =>  t('Specify where Drupal, PHP and SQL errors are logged. While it is recommended that a site running in a production environment write errors to the log only, in a development or testing environment it may be helpful to write errors both to the log and to the screen.')
   );
 
+  $form['error_page_show_blocks'] = array(
+    '#type' => 'radios',
+    '#title' => t('Blocks'),
+    '#default_value' => variable_get('error_page_show_blocks', FALSE),
+    '#options' => array(t('Hidden'), t('Visible')),
+    '#description' => t('Hide or show blocks on error reporting pages.')
+  );
+
   return system_settings_form($form);
 }
Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.710
diff -u -p -r1.710 common.inc
--- includes/common.inc	4 Nov 2007 21:24:09 -0000	1.710
+++ includes/common.inc	12 Nov 2007 02:35:48 -0000
@@ -357,8 +357,8 @@ function drupal_not_found() {
     $return = '';
   }
 
-  // To conserve CPU and bandwidth, omit the blocks.
-  print theme('page', $return, FALSE);
+  // Visibility of blocks is determined by admin setting and server load.
+  print theme('page', $return, variable_get('error_page_show_blocks', FALSE) && variable_get('throttle_level', 0) == 0);
 }
 
 /**
@@ -385,7 +385,9 @@ function drupal_access_denied() {
     drupal_set_title(t('Access denied'));
     $return = t('You are not authorized to access this page.');
   }
-  print theme('page', $return);
+
+  // Visibility of blocks is determined by admin setting and server load.
+  print theme('page', $return, variable_get('error_page_show_blocks', FALSE) && variable_get('throttle_level', 0) == 0);
 }
 
 /**