diff --git a/linkchecker.module b/linkchecker.module
index 3c58e3b..0dd55f6 100644
--- a/linkchecker.module
+++ b/linkchecker.module
@@ -429,7 +429,7 @@ function linkchecker_node_delete($node) {
  */
 function linkchecker_node_prepare($node) {
   // Node edit tab is viewed.
-  if (arg(0) == 'node' && is_numeric(arg(1)) && arg(2) == 'edit') {
+  if (arg(0) == 'node' && is_numeric(arg(1)) && arg(2) == 'edit' && isset($node->nid)) {
     // Show a message on node edit page if a link check failed once or more.
     $ignore_response_codes = preg_split('/(\r\n?|\n)/', variable_get('linkchecker_ignore_response_codes', "200\n302\n304\n401\n403"));
     $links = db_query('SELECT url, code, fail_count FROM {linkchecker_node} ln INNER JOIN {linkchecker_link} ll ON ln.lid = ll.lid WHERE ln.nid = :nid AND ll.fail_count > :fail_count AND ll.status = :status AND ll.code NOT IN (:codes)', array(':nid' => $node->nid, ':fail_count' => 0, ':status' => 1, ':codes' => $ignore_response_codes));