You need to be a bit more specific. When you say "it failed" why did it fail, how did it fail, what errors were seen (if any).
If the machines are connected properly via the network (i.e. you can ping both ways), and the ftp daemon is installed correctly (either standalone or via inetd).... I wouldn't advise logging into an ftp server as root. However, if that's what you want/have to do, check to see if
/etc/ftpusers contains a line "root". If so, delete it.
You may need to restart your FTP daemon depending on which one you use (unless you use inetd - then you won't
).
Cheers
ZB