I swear, I go through this same problem every time I set up Linux, but I keep losing track of the solution.
I have a new Linux box, kernel version 2.6.21. It is on an office lan whose others hosts are all Windows boxes. I can 'run -> ftp hostname' from any windows worstation out into the real world, but I can't ftp to this linux box. I get 'connection refused'. On the linux machine I try "ftp localhost", same thing. I have enabled proftpd in inet.conf, put "windowshost: ALL" into my hosts.allow file and done 'kill -HUP 1' to restart inetd. No go. What more do I need to do?