Slim Application Error

The application could not run because of the following error:

Details

Code: 8
Message: Undefined index: HTTP_ACCEPT_LANGUAGE
File: /web/htdocs/www.cambianella.it/home/cambianella2/files/armadillo/core/model/Armadillo_Language.php
Line: 44

Trace

#0 /web/htdocs/www.cambianella.it/home/cambianella2/files/armadillo/core/model/Armadillo_Language.php(44): Slim::handleErrors(8, 'Undefined index...', '/web/htdocs/www...', 44, Array)
#1 /web/htdocs/www.cambianella.it/home/cambianella2/files/armadillo/index.php(121): Armadillo_Language::msg('ARM_DASHBOARD_B...')
#2 [internal function]: admin()
#3 /web/htdocs/www.cambianella.it/home/cambianella2/files/armadillo/Slim/Route.php(395): call_user_func_array('admin', Array)
#4 /web/htdocs/www.cambianella.it/home/cambianella2/files/armadillo/Slim/Slim.php(1145): Slim_Route->dispatch()
#5 /web/htdocs/www.cambianella.it/home/cambianella2/files/armadillo/Slim/Middleware/Flash.php(84): Slim->call()
#6 /web/htdocs/www.cambianella.it/home/cambianella2/files/armadillo/Slim/Middleware/MethodOverride.php(91): Slim_Middleware_Flash->call()
#7 /web/htdocs/www.cambianella.it/home/cambianella2/files/armadillo/Slim/Middleware/PrettyExceptions.php(65): Slim_Middleware_MethodOverride->call()
#8 /web/htdocs/www.cambianella.it/home/cambianella2/files/armadillo/Slim/Slim.php(1097): Slim_Middleware_PrettyExceptions->call()
#9 /web/htdocs/www.cambianella.it/home/cambianella2/files/armadillo/index.php(824): Slim->run()
#10 {main}