A PHP Error was encountered

Severity: Notice

Message: Undefined index: HTTP_USER_AGENT

Filename: libraries/Mylibrary.php

Line Number: 147

Backtrace:

File: /home/manuhadsch/public_html/website/application/libraries/Mylibrary.php
Line: 147
Function: _error_handler

File: /home/manuhadsch/public_html/website/index.php
Line: 294
Function: require_once