A PHP Error was encountered

Severity: Notice

Message: Undefined index: HTTP_REFERER

Filename: controllers/En.php

Line Number: 21

Backtrace:

File: C:\inetpub\wwwroot\psthai\application\controllers\En.php
Line: 21
Function: _error_handler

File: C:\inetpub\wwwroot\psthai\index.php
Line: 292
Function: require_once