Help with facebbok.el

[Exal Garcia Carrillo]

Hi, does anyone use facebook.el?, I'm getting the following error when 
I try the M-x facebook-login: 

,---- 
| Wrong type argument: characterp, (request_args . [((value . "d33a5eafc72c6324576c1bd1319910a21") (key . "sig")) ((value . "") (key 
|."api_key")) ((value . \"1978692874445\ 
| 856") (key . "call_id")) ((value . "JSON") (key . "format")) 
((value . "auth.createToken") (key . "method")) ((value . "1.0") 
(key . "v"))]) 
`---- 

My only related line on ~/.emacs is (require 'facebook)

(I have loaded json.el also) 

I'm using emacs 23 (installed from the repos) on a debian lenny box 

any hint or advice will be really appreciated 

thanks, Exal