This may be obvious, but don't forget to do "make autoloads" after a "git clone": http://orgmode.org/manual/Installation.html
I was getting: "Symbol's function definition is void: org-export-dispatch" and wasted time trying to figure this out. This posting is to document it the mailing list so others experiencing the same symptom can find the solution, even it it is "well, duh"/RTFM. ---George Jones