Setting Up PHP behind Nginx with FastCGI

Question

I am trying to set up PHP on my server running nginx as reverse proxy. I have the following directive in the configuration file:

location ~ \.php(/|$) {
    fastcgi_split_path_info ^(.+?\.php)(/.*)$;
    fastcgi_pass unix:/var/run/php5-fpm.sock;
    include fastcgi_params;
}

On opening any php script on the browser it says 500 Internal server error . If I completely comment out this directive, the browser throws a dialog box giving an option to download the php script. All other files like image files etc. in the same directory as the php scripts are accessible. Where can there be a problem?

EDIT: The configuration file

upstream the_server {
server localhost:8000;
}

server {
    root    /var/www/linux-dash-master;
    listen  80;
    client_max_body_size    4G;
    keepalive_timeout       5;
    log_format timed_combined '$sent_http_x_username - $remote_addr - [$time_local]  '
    '"$request" $status $body_bytes_sent '
    '"$http_referer" "$http_user_agent" - '
    '$request_time $upstream_response_time $pipe';
    access_log  /var/log/nginx/named.access.log timed_combined;
    error_log  /var/log/nginx/named.error.log debug;
    location /linux-dash-master {
            alias /var/www/linux-dash-master;
            index index.html index.php;
    }
    # Pass PHP requests on to PHP-FPM using sockets
    location ~ /linux-dash-master/.*\.php(/|$) {
            alias /var/www/linux-dash-master;
            #fastcgi_pass   127.0.0.1:9000;
            fastcgi_index  index.php;
            fastcgi_intercept_errors on;
            if ($fastcgi_script_name ~ /linux-dash-master(/.*\.php)$) {
                    set $valid_fastcgi_script_name $1;
            }
            fastcgi_param SCRIPT_FILENAME /var/www/linux-dash-master$valid_fastcgi_script_name;
            #fastcgi_split_path_info ^(.+?\.php)(/.*)$;
            fastcgi_pass unix:/var/run/php5-fpm.sock;
            try_files $uri $uri/ /index.php?$args;
            #include fastcgi_params;
      }
      location /static/ {
          alias   /path/to/staticfiles/;
      }
      location / {
          proxy_pass          http://the_server;
          proxy_set_header    Host            $host;
          proxy_set_header    X-Real-IP       $remote_addr;
          proxy_set_header    X-Forwarded-For $proxy_add_x_forwarded_for;
          proxy_set_header    X-Remote-User-Name   $remote_user;
      }

}

Answer 1

Check /etc/php5/fpm/pool.d/www.conf does it exist?

If so check inside it, look for a line that starts with listen , does it point for a file or a port ?

Note that lines starting with ; don't count