Error 404 at logging on phpmyadmin with Nginx

Question

I have an error 404 when I connect me on Phpmyadmin on my server like: http://url/phpmyadmin

I obtain the phpmyadmin page but when I click on "Execute", I obtain an error 404

On my default file on Nginx, sites-available, I add that:

location /phpmyadmin {
    root /usr/share/;
    index index.php index.html index.htm;
    location ~ ^/phpmyadmin/(.+\.php)$ {
            try_files $uri =404;
            root /usr/share/;
            fastcgi_pass unix:/var/run/php5-fpm.sock;
            fastcgi_index index.php;
            fastcgi_param SCRIPT_FILENAME $request_filename;
            include /etc/nginx/fastcgi_params;
            fastcgi_param PATH_INFO $fastcgi_script_name;
            fastcgi_buffer_size 128k;
            fastcgi_buffers 256 4k;
            fastcgi_busy_buffers_size 256k;
            fastcgi_temp_file_write_size 256k;
            fastcgi_intercept_errors on;
    }
    location ~* ^/phpmyadmin/(.+\.(jpg|jpeg|gif|css|png|js|ico|html|xml|txt))$ {
            root /usr/share/;
            }
    }
    location /phpMyAdmin {
            rewrite ^/* /phpmyadmin last;
    }

Why I can't to connect ? Have I forgot to do an configuration?