Ok, I am a bit confused on what the trouble is ..
doesnt the connection work when you use an IP like say 192.168.xxx.xxx ?
Just some pointers, if you do want to look at whats going on..
the conf files are in /etc/proftpd.conf or /usr/local/etc/proftpd.conf
are you using it as a standalone or are you using it via inetd, I would recommend having it loaded thru inetd if you dont have too much to FTP. If you are using inted then you need to change the /etc/inetd.conf to run proftpd; if not comment out the entire FTP line from /etc/inetd.conf
ok to simplify .. check out:
http://www.mandrakeuser.org/docs/connect/
and try to see where you have gone wrong. Also check your /etc/hosts file to see if your IPs are layed out correctly.