I had the same problem: uninstalling proftpd did not completely clean the /etc/inetd.conf file, and let a "ftp " line in comments.
/etc/init.d/wu-ftpd start greps "ftp " in /etc/inetd.conf, without ignoring comments. It found a line containing "ftp " but it should not. This could be corrected if comments were ignored.
I had the same problem: uninstalling proftpd did not completely clean the /etc/inetd.conf file, and let a "ftp " line in comments.
/etc/init.d/wu-ftpd start greps "ftp " in /etc/inetd.conf, without ignoring comments. It found a line containing "ftp " but it should not. This could be corrected if comments were ignored.