500 error page, I don't know why

With no apparently reason the site www.promozionecasa.com with JUX REAL ESTATE went down yesterday. Now the only page I see is 500 error.
Can you help me?

ftp user: promoga
pass: fubyxO6841

srv01.ctm-matinella.it/phpmyadmin
DB: promo_011
pass: vjrKK3211d

Thanks

Hi,
Thanks for choosing our product.
About your problem, I can't access with your ftp account. You can check it help me.
Also, to security, please give me your account via PM, not via forum.
Thanks.