When you want to use fully this FTP server you face problem of passive connections, especially in case of using firewall.
Solution is to setup passive port range for FTP server and then setup your firewall properly using this range.
To do this, use some VBS help using cmd window:
cd c:\Inetpub\AdminScripts
adsutil.vbs set /MSFTPSVC/PassivePortRange "5100-5120"
It is important to use range between 5001 and 65535, if you use lower ports FTP server won't startup.