404 Not found Error

1. It is set to $config['base_url'] = 'http://localhost/accounting';

This is probably the problem. More than likely, the base URL should simply be http://localhost/ (and in that case, you could leave it empty), unless you have specifically configured the local server to use the URL http://localhost/accounting/ as the base URL for this site.

For a localization project, you shouldn't have to change any code once you have the site configured correctly in your development environment, unless they have never localized the site into any other languages (in which case you may have to create language strings for the site's original language and the new language and ensure that views and controllers use the language strings instead of hard-coded text).

Thank you @mwhitney for the response. I have solved the problem, the problem was with my .htaccess file. I only had to change the RewriteBase / to RewriteBase /accounting/ .     Since my virtual host is set to accounting.dev I have set the base_url parameter to $config[base_url]='http://localhost/accounting'. For me it works this way. Thank you for the response!