The url is http://dev.flow3.local/flow3/welcome
Here is the error
CreateFile() "C:\nginx/htmlindex.php/flow3/welcome" failed (3: The system
cannot find the path specified)

This is horribly wrong. I'm using try_files for a very simple rewrite rule.
my server code is
server {
listen 80;
server_name dev.flow3.local;

location / {
root html/flow3/Web;
index index.php;
try_files $uri $uri/ index.php$uri;

}
error_page 500 502 503 504 /50x.html;

# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
location ~ \.php$ {
root html/flow3/Web;
fastcgi_connect_timeout 120;
fastcgi_send_timeout 180;
fastcgi_read_timeout 180;
fastcgi_pass 127.0.0.1:9000;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME
$document_root$fastcgi_script_name;
include fastcgi_params;

}

location ~ /\.ht {
deny all;
}
}