PSpell doesn't work

Hi,

I'm trying to use the PHP PSpell plugin to create a spellchecking script, but the PSpell doesn't work.

I know PSpell plugin is installed on the server.
I can see it on the phpinfo.

However, when I try to call PHP pspell_new it returns :
Warning: pspell_new() [function.pspell-new]: PSPELL couldn't open the dictionary. reason: No word lists can be found for the language "en".
This is a single command :
$pspell_link = pspell_new("en");
http://www.russianartdealer.com/spell/spell.php

What goes wrong?

Thanks in advance.
Mino