Gnus Cannot Connect Gmail

[narke]

followed the guides of http://www.pvv.ntnu.no/~terjeros/wiki/GnusGmail,
i was going to setup Gnus work with Gmail.  i've got and updated the
three lisp scripts as described, lisp/mail/smtpmail.el,
lisp/starttls.el, pop.el respectively. but after i start Gnus and
provide my gmail password after the question, i only got an error and
failed in the connection,

  Mail source error ((file-error Cannot open load file ssl)).

does anyone know what is the problem?  below is my .gnus configuration.

thanks in advance.

--
narke


--------.gnus--------
;; The following line is needed when using pop3.el from T-gnus
(m17n.org).
(eval-after-load "mail-source" '(require 'pop3))

;; newsgroups name encoding
;;
(setq gnus-group-name-charset-group-alist
      '((".*" . cn-gb-2312)))

;; fetch primary nntp server
;;
(setq gnus-select-method '(nntp "news.gnus.org"))

;; for additional nntp servers need to fetch from
;;
;; (add-to-list 'gnus-secondary-select-methods '(nntp "news.cn99.com"))

;; fetch local spool directory
;;
;; (add-to-list 'gnus-secondary-select-methods '(nnspool ""))
;; (add-to-list 'gnus-secondary-select-methods
;;             '(nnspool "" (nnspool-directory
"/usr/local/myspoolddir")))

;; the back end used for incoming mail messages.
;;
;; (setq gnus-secondary-select-methods
;;      '((nnml "private"))
(add-to-list 'gnus-secondary-select-methods '(nnml ""))

(setq gnus-posting-styles
      '((".*"
         (name "Steven Woody")
         (address "narke@narke.yellow.line"))
        ("^nnml.*gmail"
         (address "narkewoody@gmail.com"))))


(setq mail-sources
      '((file :path "/var/spool/mail/narke")
        (pop :server "pop.gmail.com"
             :port 995
             :user "narkewoody"
             :connection ssl
             :leave t)))


(defun fs-change-smtp ()
  "Change the SMTP server according to the current from line."
  (save-excursion
    (let ((from
           (save-restriction
             (message-narrow-to-headers)
             (message-fetch-field "from"))))
      (message "From is `%s', setting `smtpmail-smtp-server' to `%s'"
               from
               (cond
                ((string-match "narkewoody@gmail.com" from)
                 ;; Use stmp-auth
                 (message "Using smtp-auth")
                 ;; Sending mail
                 (setq message-send-mail-function 'smtpmail-send-it)
                 (setq smtpmail-starttls-credentials '(("smtp.gmail.com" 587 nil
nil)))
                 (setq smtpmail-auth-credentials '(("smtp.gmail.com" 587 
"joeuser"
nil)))
                 (setq smtpmail-default-smtp-server "smtp.gmail.com")
                 (setq smtpmail-smtp-server "smtp.gmail.com")
                 (setq smtpmail-smtp-service 587))
                ((string-match "narke@narke.yellow.ling" from)
                 ;; Use local sendmail
                 (message "Using local sendmail")
                 (setq message-send-mail-function 
`message-send-mail-with-sendmail))
                (t
                 (error
                  (concat "Don't know which mail server to use for "
                          from))))))))

(add-hook 'message-setup-hook 'fs-change-smtp)
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