FYI, the latest Aquamacs Preview 5 solved the "Refile error - kill is not a
(set of) trees"
problem (at least for me).

http://www.mail-archive.com/emacs-orgmode@gnu.org/msg14756.html

I downloaded the newest version, and ran it with
Org-mode version 6.34trans (release_6.34c.243.g2bca7.dirty)

http://aquamacs.org/download.shtml

--Nate