MacFan is, as you have probably surmised by this point, no longer being actively developed.
It has come to my attention that there is a program under development which currently interfaces directly with Apple's drivers to monitor temperatures and fan speeds. I suggest you follow along with the progress being made by the developer in this thread, until such time as that developer hopefully creates a sourceforge project of his own and adds fan control: http://sourceforge.net/projects/lubbofancontrol/forums/forum/970570/topic/3714669.
Ironically, I will have more free time in the coming months. If I see that little progress is being made on fan control by this developer using his far superior method, I will reconsider resuming development of this program and quashing the bugs which have been reported. However, I am hopeful that this developer will usher in a new elegant method of fan control, rendering this project irrelevant.
It's a shame you stopped development on this since Lubbo's FanControl actually isn't superior. You app works with all three fans in my 2011 iMac while Lubbo assumes at most two fans and sets the wrong ones to bad values.
Your app still works though so maybe I'll take a crack at adding a GUI.
Thanks for all your work.
Lubbo's fan doesn't support iMac. He has mentioned it on the forum itself.