Okay, this is a long shot, but give it a try as I had to do this when using FVP5000T.
On Windows, go to the "Control Panel". From the left-hand side, select "Turn Windows Features On or Off" Find "SMB 1.0/CIFS File Sharing Support"
Go into drop-down and select SMB 1.0/CIFS Client.
You will get some security warnings, for now just ignore them as you can always untick the box later on.
Save this and see if ftp works - with port 2323.