diff --git a/mod/forum/post.php b/mod/forum/post.php
index 3cfea5bb891..1ff1b7d374d 100644
--- a/mod/forum/post.php
+++ b/mod/forum/post.php
@@ -169,7 +169,7 @@
         $defaultformat = FORMAT_MOODLE;
     }
 
-    $parent=NULL;  // Initialise some things
+    $parent = new stdClass;  // Initialise some things
 
 
     if (isset($post->error)) {     // User is re-editing a failed posting