Nginx iRedMail roundcube error

==== Required information ====
- iRedMail version:
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):
- Linux/BSD distribution name and version:
- Related log if you're reporting an issue:
======== Required information ====
- iRedMail version: iRedMail-0.8.5
- Store mail accounts in which backend (MySQL):
- Linux/BSD distribution name and version: CentOS 6.4
- Related log if you're reporting an issue:

tail -f /var/www/roundcubemail/logs/errors
[17-Sep-2013 19:05:17 +0000]: DB Error: Configuration error. Unsupported database driver:  in /var/www/roundcubemail-0.9.2/program/lib/Roundcube/rcube_db.php on line 75 (GET /)
[17-Sep-2013 19:05:21 +0000]: DB Error: Configuration error. Unsupported database driver:  in /var/www/roundcubemail-0.9.2/program/lib/Roundcube/rcube_db.php on line 75 (GET /)
[17-Sep-2013 19:05:21 +0000]: DB Error: Configuration error. Unsupported database driver:  in /var/www/roundcubemail-0.9.2/program/lib/Roundcube/rcube_db.php on line 75 (GET /)
[17-Sep-2013 19:05:22 +0000]: DB Error: Configuration error. Unsupported database driver:  in /var/www/roundcubemail-0.9.2/program/lib/Roundcube/rcube_db.php on line 75 (GET /)

====

Hi all,

This is my first time using iRedMail and for the first time it's work like a charm I'm using Apache as the web server to serve the webmail and the iredadmin. Both work with no errors.

Since my customer want to used Nginx, I've already configured uwsgi to server the iredadmin and it's also work. But except the roundcube, When I start the php_cgi and try to access the webmail it gives a blank page and the errors as above.

Does anyone encounter same like me ?

nginx webmail.conf :

server {
        listen 443 ssl;
        server_name svr2.mydomain.my;

        access_log /var/log/nginx/webmail.access.log;
        error_log /var/log/nginx/webmail.error.log;

    root   /var/www/roundcubemail/;
    index  index.php;

        location ~ \.php$ {
        root    /var/www/roundcubemail/;
                fastcgi_pass   127.0.0.1:9000;
                fastcgi_index  index.php;
                include fastcgi_params;
                fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_param SERVER_NAME $http_host;
                fastcgi_ignore_client_abort on;
        }

    ssl                  on;
        ssl_certificate      /etc/pki/tls/certs/iRedMail_CA.pem;
        ssl_certificate_key  /etc/pki/tls/private/iRedMail.key;
        ssl_session_timeout  5m;
        ssl_protocols  SSLv2 SSLv3 TLSv1;
        ssl_ciphers  ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP;
        ssl_prefer_server_ciphers   on;

}

Thanks in advance.