[O] babel setup

[Shiyuan]

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