Index: modules/block/block.admin.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/block/block.admin.inc,v
retrieving revision 1.23
diff -u -p -r1.23 block.admin.inc
--- modules/block/block.admin.inc	20 Oct 2008 13:00:24 -0000	1.23
+++ modules/block/block.admin.inc	25 Oct 2008 19:38:08 -0000
@@ -38,7 +38,7 @@ function block_admin_display_form(&$form
 
   // Build the form tree.
   $form = array(
-    '#action' => arg(3) ? url('admin/build/block/list/' . $theme_key) : url('admin/build/block'),
+    '#action' => (arg(3) && arg(4)) ? url('admin/build/block/list/' . $theme_key) : url('admin/build/block'),
     '#tree' => TRUE,
   );