ERC and Nickserv

Hi, 

i can't get working the ERC Nickserv and i don't understand why. Nothing is sent
to nickserv when i connect. Here's my configuration:

; ERC (extensible IRC client)
; Set used modules
(require 'erc)
(require 'erc-services)
(load "ercpass")
 '(erc-modules (quote (autojoin button completion fill irccontrols match menu
netsplit noncommands readonly ring scrolltobottom smiley stamp track services)))

(setq erc-services-mode 1)
(setq erc-autojoin-mode 0)
(setq erc-prompt-for-nickserv-password t 
      erc-user-full-name "gnunix"
      erc-email-userid "gnunix")
;(add-hook 'erc-server-NOTICE-functions 'send-post-cloak-autojoin)

(setq erc-nickserv-passwords
      `((freenode     (("ninix" . ,erc-nickserv-password-tmp)
                       ("s0nix" . ,erc-nickserv-password-tmp)))))

(defun erc-start()
  (interactive)
  (setq erc-autojoin-channels-alist
        (list (cons "freenode.net" erc-autojoin-channels-tmp)))
  (erc-select :server "irc.freenode.net" :port 6667 :nick erc-nickname-tmp))

Also, there is something that i can't figure out..... even if i set
"erc-autojoin-mode" to 0... after the erc-start() the autojoin is executed and
if i recheck the value of "erc-autojoin-mode", it is come back to 1.

Any hint ?

Thanks
Alan