A PHP Error was encountered

Severity: Notice

Message: Undefined index: HTTP_ACCEPT_LANGUAGE

Filename: controllers/Signup.php

Line Number: 16

Backtrace:

File: /usr/share/nginx/www/DBaaSValet/congress/abstractapp/application/controllers/Signup.php
Line: 16
Function: _error_handler

File: /usr/share/nginx/www/DBaaSValet/congress/abstractapp/index.php
Line: 315
Function: require_once