I think this has to do with autoload, but I am not an emacs or org expert.

Try making sure that (package-initialize) comes before any org functions in your .emacs (from the answer here).

HTH,
Jake


On Mon, Jun 9, 2014 at 1:18 AM, Shiyuan <gshy2014@gmail.com> wrote:
Hi all, 
      I am using Emacs 24.3.9 + org-mode 8.2.6(from ELPA) 

and added the following to my .emacs file. 

(org-babel-do-load-languages
  'org-babel-load-languages
  '((python . t)
    (emacs-lisp . t)))

After that, org-mode mysteriously switched back to the old version 7.9.  Another problem is that export command C-c C-e no longer works and generates error: Symbol's function definition is void: org-defvaralias. Is there any step I missed? Thanks. 

Shiyuan