new voices in festival

["Jordi Colomer Matutano" <jordicolomer@hotmail.com>]

i've just installed festival, and works correctly with the default voice, 
but then i wanted to try another voice, but i get an error.
this is what i've done:

install festival, and this extra voices:
festvox-ellpc11k
festvox-don
festvox-kdlpc16k
festvox-rablpc16k

but when i try to change the voice with any of these commands 
(respectively):
voice_el_diphone
voice_don_diphone
voice_ked_diphone
voice_rab_diphone

i get the following error:

#<CLOSURE n (let ((me voice_el_diphone)) (require 
"/usr/share/festival/voices/spanish/el_diphone/festvox/el_diphone") (if (eq 
me voice_el_diphone) (error (string-append "autoload: \"" 
"/usr/share/festival/voices/spanish/el_diphone/festvox/el_diphone" ".scm\" 
does not define " (quote voice_el_diphone)))) (apply voice_el_diphone n))>

and this happens to all extra voices, the only one that seems to work 
correctly is voice_kal_diphone, that is the default one

can any one help me?
thanks in advance, and sorry for my poor english