Translation themes NOT working

I've got a gallery 2 installed on my website and I've got the website translated into different languages. I'm working with legacy code so I can't give you much information about the gallery or the website, but I can see that there are different themes for all the different languages and they're linked like this: http://www.babylon-idiomas.com/gallery-new/main.php?g2_language=es.

And this is the php to trigger the different themes:
<?php
//File for configuring the theme according to a language
$theme_language=array(
"es"=>"esbabylon",
"it"=>"itbabylon",
"fr"=>"frbabylon",
"de"=>"debabylon",
"nl"=>"nlbabylon",
"en"=>"matrix",
"pt"=>"ptbabylon",
"sv"=>"sebabylon",
"jp"=>"jpbabylon"
);
?>

Problem is

the language=es is not working and it's going to the main matrix theme...

What do you think it could be?

Thanks a bunch,

Guillem

Thought so... what else would you need?