index.php/ on url of all pages in the website

Hi, I have installed Fortuna and I have imported the demo data.
I see that all pages have this url http://nebulasgraphics.it/elisaserrau/index.php/contatti/.
Infact in the permalink section, there a custom url whith this settings /index.php/%year%/%monthnum%/%day%/%postname%/

If I delete index.php the pages doesn’t works.
There’s a way to remove index.php from the url?

Thank you very much