Mark read goes to blank page

Elgg version 1.7.5

Page going to blank page when we click "mark read " button after selecting the message from inbox.

patch :

Index: mod/messages/actions/delete.php
===================================================================
--- mod/messages/actions/delete.php   
+++ mod/messages/actions/delete.php   
@@ -58,7 +58,7 @@
             if($type == 'sent'){
                 forward("pg/messages/sent/?offset={$offset}");
             }else{
-                forward("mod/messages/inbox/" . get_loggedin_user()->username . "?offset={$offset}");
+                forward("pg/messages/inbox/" . get_loggedin_user()->username . "?offset={$offset}");
             }
         } else {
             register_error(elgg_echo("messages:notfound"));