nginx - problem with change location root folder

Hi ,

I've created the new website with use ispconfig and path to this is /var/www/myweb.com/web/ . All is ok but main folder to this website I must set up like /var/www/myweb.com/web/mainpage . so then I've added in Options to field "nginx Directives" such code:

Code:

 location / {
 root /var/www/myweb.com/web/mainpage; 
 }

And here is problem. if I type in browser myweb.com then works only if in folder /mainpage is index.html but doesn't if index.php. If I delete index.html and will be only index.php then I have error 404 not found.

My vhost config:

Code:

server {
        listen *:80;


        server_name myweb.com www.myweb.com;




        index index.html index.htm index.php index.cgi index.pl index.xhtml;



        error_page 400 /error/400.html;
        error_page 401 /error/401.html;
        error_page 403 /error/403.html;
        error_page 404 /error/404.html;
        error_page 405 /error/405.html;
        error_page 500 /error/500.html;
        error_page 502 /error/502.html;
        error_page 503 /error/503.html;
        #recursive_error_pages on;
        location = /error/400.html {

            internal;
        }
        location = /error/401.html {

            internal;
        }
        location = /error/403.html {

            internal;
        }
        location = /error/404.html {

            internal;
        }
        location = /error/405.html {

            internal;
        }
        location = /error/500.html {

            internal;
        }
        location = /error/502.html {

            internal;
        }
        location = /error/503.html {

            internal;
        }

        error_log /var/log/ispconfig/httpd/myweb.com/error.log;
        access_log /var/log/ispconfig/httpd/myweb.com/access.log combined;

        location ~ /\. {
            deny all;
            access_log off;
            log_not_found off;
        }

        location = /favicon.ico {
            log_not_found off;
            access_log off;
        }

        location = /robots.txt {
            allow all;
            log_not_found off;
            access_log off;
        }

        location /stats/ {

            index index.html index.php;
            auth_basic "Members Only";
            auth_basic_user_file /var/www/clients/client0/web15/web/stats/.htpasswd_stats;
        }

        location ^~ /awstats-icon {
            alias /usr/share/awstats/icon;
        }

        location ~ \.php$ {
            try_files /7194346190f40f4d88f625a2623a6600.htm @php;
        }

        location @php {
            try_files $uri =404;
            include /etc/nginx/fastcgi_params;
            fastcgi_pass unix:/var/lib/php5-fpm/web15.sock;
            fastcgi_index index.php;
            fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
            fastcgi_intercept_errors on;
        }
location / {
root   /var/www/myweb.com/web/mainpage;
}


}