The connection is most probably blocked by the Windows firewall.
While the Windows firewall is automatically configured with rules for the ports 21, 990 and 1024-65535, when IIS FTP server is installed, the rules are not enabled initially.
To enable or change the rules, go to Control Panel > System and Security > Windows Firewall > Advanced Settings ...
The solution was to create a small physcial partition to house directory symbolic links to the server locations.
Creates a symbolic link.
MKLINK [[/D] | [/H] | [/J]] Link Target
/D Creates a directory symbolic link. Default is a file
/H Creates a hard link instead of a symbolic link....