diff --git a/template.php b/template.php
index 7ad141d9add75cc4414b95b15b4335baf61d25e0..6a0e4c6c5908569d5f2734bd7d249534709a39f5 100644
--- a/template.php
+++ b/template.php
@@ -192,7 +192,7 @@ function zen_preprocess_html(&$variables, $hook) {
       if ($arg[1] == 'add') {
         $section = 'node-add';
       }
-      elseif (is_numeric($arg[1]) && ($arg[2] == 'edit' || $arg[2] == 'delete')) {
+      elseif (isset($arg[2]) && is_numeric($arg[1]) && ($arg[2] == 'edit' || $arg[2] == 'delete')) {
         $section = 'node-' . $arg[2];
       }
     }