diff --git a/modules/block/block.admin.inc b/modules/block/block.admin.inc
index 17f854f2965..a8f515d031e 100644
--- a/modules/block/block.admin.inc
+++ b/modules/block/block.admin.inc
@@ -38,7 +38,7 @@ function block_admin_display_form(&$form_state, $blocks, $theme = NULL) {
 
   // Build the form tree.
   $form = array(
-    '#action' => arg(3) ? url('admin/build/block/list/' . $theme_key) : url('admin/build/block'),
+    '#action' => arg(4) ? url('admin/build/block/list/' . $theme_key) : url('admin/build/block'),
     '#tree' => TRUE,
   );