Hi all,
      I am using Emacs 24.3.9 + org-mode 8.2.6(from ELPA)
      I followed this instruction
http://orgmode.org/worg/org-contrib/babel/languages.html#configure

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