A PHP Error was encountered

Severity: Notice

Message: Undefined index: HTTP_REFERER

Filename: controllers/Registration.php

Line Number: 25

Backtrace:

File: /home/q2wjiyf480ou/public_html/application/controllers/Registration.php
Line: 25
Function: _error_handler

File: /home/q2wjiyf480ou/public_html/index.php
Line: 315
Function: require_once