WP installed is asking to install if typed domain.com

Adding this lines to .htacces solved the redirect problem to wp-admin/install.php if typed the domain.com without the www even if the WP was completely installed and settings configured properly.

RewriteCond %{HTTP_HOST} ^www.domain.com/rus [NC]
RewriteRule ^$ /index.php [NC,L]

Now I can continue with rusian translation.

The main problem was a defective plugin, which was blocking the Adminn panel and routines that checks the config file; the error on the plugin was a wrong coded lines with non UTF-8 Format.