The specific actions available via ftpdctl depend on the modules compiled into proftpd. Check the modules documentation for more information on the specific actions supported by the modules.
ProFTPD is written and maintained by a number of people, full credits can be found on http://www.proftpd.org/credits.html
Full documentation on ProFTPD, including configuration and FAQs, is available at http://www.proftpd.org/
For help/support, try the ProFTPD mailing lists, detailed on http://www.proftpd.org/lists.html
Report bugs at http://bugs.proftpd.org/