I am a R user, I want to use R in emacs. But, I am in trouble with customizing ess in emacs. I have installed the auto-complete packages and the latest ess in my emacs. But when I run r in emacs, the auto-complete don't work well. When I type app, I suppose to show like the image in (http://www.emacswiki.org/pics/static/ess-ac3) , but in my emacs neither of the auto-complete nor the yellow part shows.
My OS: ubuntu 12.04 amd64
my ~/.emacs file
;; Auto-complete
(add-to-list 'load-path "~/.emacs.d/site-lisp")
(require 'auto-complete-config)
(add-to-list 'ac-dictionary-directories "~/.emacs.d/site-lisp/ac-dict")
(ac-config-default)
; ess-site
(add-to-list 'load-path "/usr/share/emacs/site-lisp/ess")
(require 'ess-site)
(setq ess-eval-visibly-p nil)
(setq ess-ask-for-ess-directory nil)