In your ftp server you should be able to set a root folder (could be c:\ftp or something similar). The ftp client does not need to know the path on the actual server, it just connects with ftp and gets the contents of the configured root folder.
So on the ftp client you should not use "cd c:\...", since that is an invalid path from client point of view.
If the root on the ftp server is c:\ftp and it contains a folder \backup (so c:\ftp\backup), the ftp client should just connect and use "cd backup" to get to the subfolder.
Next part is the local config files on the controller. You can use on the controller "dir" to see the local files. There might be mutiple configuration files (*.cfg), so with "display startup" you can see which of these configuration files is used by the system.
Now you should be able to use ftp and get/put commands to download or upload files.
Make sure the windows ftp server allows creation of files/folders (both at windows level and at ftp software (user rights) level).