Problems with routes in CodeIgniter

I'm trying to run a code in CodeIgniter on my computer with Kubuntu. To access the home ( link ) does not have any problem, however, when I try to access the other URL ( link ) the message "The requested URL / client was not found on this server."

My .htaccess:

RewriteBase /
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?/$1 [L]

The routes.php file:

$route['default_controller'] = 'welcome';
$route['404_override'] = '';
$route['translate_uri_dashes'] = FALSE;

$route['cliente'] = 'clientes';
$route['produto'] = 'produtos';

I have the Clients.php and Products.php files in the application / controllers folder.

In the config.php file: $ config ['index_page'] = '';

The weirdest thing is that to access home has no problem. Just the problem when I try another URL type link .

Thanks for the help.