Installing haskell-mode into Emacs on Ubuntu 12

I'm following these instructions to install haskell-mode on Ubuntu 12. However when I get to the point of typing M-x customize-option RET pac then Emacs says: no match! All the customizable variables are shown in the picture below.

Any idea what is going wrong?

Go to your init.el file (~/.emacs.d/init.el) and place this there:

(setq package-archives
      '(("gnu"         . "http://elpa.gnu.org/packages/")
        ("original"    . "http://tromey.com/elpa/")
        ("org"         . "http://orgmode.org/elpa/")
        ("marmalade"   . "http://marmalade-repo.org/packages/")
        ("melpa" . "http://melpa.milkbox.net/packages/")))

(package-initialize)

And then do M-x package-refresh-contents and you can install haskell-mode from there. Also make sure that your Emacs version is >= 24 since package.el is bundled with only higher version. If you are using older version, you may have to manually install that package.