Urgent! Web made with CI is not being displayed in mobile devices

[eluser]luismartin[/eluser]
I need your help to find out why this web is not being displayed in mobile devices (iPad, iPhone, Android, Blackberry etc):

http://www.sonia-sa.com

A blank page is displayed instead in iPhone/iPad. It works fine in common browsers (FF, Chrome, IE, Opera...)

I've already done some tests such as commenting out all the CSS and JS links and inline code. In this case I also get a blank page, so it's not due to CSS/JS. The Blackberry displays a 500 status error. I've tried to serve the index page as a plain html copied and pasted from the resulting home page and this is being correctly displayed in iPhone. So I think I can definitely discard any doctype, html, js, or css error.

My suspicions now are on PHP/Codegniter and Apache.

Is there anything I must do in CodeIgniter in order to allow a web to be viewed in mobile devices? If not, I would really appreciate any suggestion.