Get the sftp binary from here

Connect Kindle in USB mode and copy this file to any dir.

Start Putty and ssh to [email protected] Password is mario

Now, manually copy that file from /mnt/us/location_where_copied to /usr/libexec/

chmod 755

Now try sftp to [email protected] with port 22 and password mario

You can now copy files to and fro..

 

If you prefer a File manager interface for copying files though, use WinSCP