This is not really a wu-ftpd problem, but as proftpd isn't
an option ... ;)
Basically, the default configuration for proftpd is
standalone and the startup scripts are missing. It looks as
though it was destined to be added to the inetd.conf file,
because an in.proftpd file is installed in /usr/sbin, but
the default config says standalone ...
The proftpd-1.2.0pre6-3 should be working. I restarted inetd on my
local machine after installing proftpd and it works. Are you using a
previous version or the one I am using?