I had the same problem some time ago. That variable
has been removed in recent Org versions, and you
probably have (like me) an old built-in Org "shadowed"
by a new Elpa Org. You should ignore that variable.
See previous discussion and some advices here:
http://permalink.gmane.org/gmane.emacs.orgmode/77193
http://permalink.gmane.org/gmane.emacs.orgmode/77241