How to install ProFTPd on Redhat (Was: Baffled.....)

I have been trying to install Proftpd on RedHat 7.3 and have run into a problem that is beyond me.... I bought a dial-up account for the express purpose of setting this up and debugging it - and here's what happens: using dial-up, I log in with no problem (using Windows 2000 and CuteFTP). However, virtually everyone else that tries to connect gets a "failure to connect data socket" error. I'm fairly new to Linux and not much of a techie but this just seems so weird. When I have disabled my ethernet card and I'm connected to MSN on a telephone line I'm as "global' as anyone. I'm using the example anonymous config and added the line "PassivePorts 60000 65535" per a doc I found on Google. When I installed RedHat I ticked all of the network servers. I'm on a LAN but the PC in question is in the DMZ and, also, has all of the appropriate ports mapped (which may be redundant as it's in the DMZ). Any help would be greatly appreciated. The server just has some Linux ISOs, the IP is:
67.162.223.205 - can also be resolved by way of: guyster.dtdns.net