Slim Application Error

The application could not run because of the following error:

Details

Code: 2
Message: Undefined array key "HTTP_ACCEPT_LANGUAGE"
File: /var/www/vhosts/bomiltech.com/httpdocs/Nieuws/files/armadillo/core/model/Armadillo_Language.php
Line: 44

Trace

#0 /var/www/vhosts/bomiltech.com/httpdocs/Nieuws/files/armadillo/core/model/Armadillo_Language.php(44): Slim::handleErrors()
#1 /var/www/vhosts/bomiltech.com/httpdocs/Nieuws/files/armadillo/index.php(121): Armadillo_Language::msg()
#2 /var/www/vhosts/bomiltech.com/httpdocs/Nieuws/files/armadillo/Slim/Route.php(395): admin()
#3 /var/www/vhosts/bomiltech.com/httpdocs/Nieuws/files/armadillo/Slim/Slim.php(1145): Slim_Route->dispatch()
#4 /var/www/vhosts/bomiltech.com/httpdocs/Nieuws/files/armadillo/Slim/Middleware/Flash.php(84): Slim->call()
#5 /var/www/vhosts/bomiltech.com/httpdocs/Nieuws/files/armadillo/Slim/Middleware/MethodOverride.php(91): Slim_Middleware_Flash->call()
#6 /var/www/vhosts/bomiltech.com/httpdocs/Nieuws/files/armadillo/Slim/Middleware/PrettyExceptions.php(65): Slim_Middleware_MethodOverride->call()
#7 /var/www/vhosts/bomiltech.com/httpdocs/Nieuws/files/armadillo/Slim/Slim.php(1097): Slim_Middleware_PrettyExceptions->call()
#8 /var/www/vhosts/bomiltech.com/httpdocs/Nieuws/files/armadillo/index.php(824): Slim->run()
#9 {main}