Summary
The remote host is missing an update to the system as announced in the referenced advisory.
Solution
Update your system with the appropriate patches or software upgrades.
http://seclists.org/fulldisclosure/2011/Nov/452
http://www.vuxml.org/freebsd/022a4c77-2da4-11e1-b356-00215c6a37bb.html
Insight
The following packages are affected:
proftpd
proftpd-mysql
proftpd-devel
