As stated by jggimi, just adding a new variable to rc.conf/rc.conf.local won't automagically make things work.
The preferred method of starting 3rd party services at boot time is in
rc.local(5), you probably should only start daemons/servers that properly support privilege separation using this method.
The alternative is to create a lesser privileged account and start it manually, if the software listens on a port <= 1024 by default, you can bind it to a higher port and use pf to redirect traffic.
Hope that helps.