A PHP Error was encountered

Severity: Notice

Message: Undefined index: HTTP_REFERER

Filename: controllers/Cart.php

Line Number: 657

Backtrace:

File: /var/www/buyer/application/core/MY_Exceptions.php
Line: 190
Function: include

File: /var/www/buyer/application/controllers/Cart.php
Line: 657
Function: _error_handler

File: /var/www/buyer/index.php
Line: 333
Function: require_once