Hello Vicenzo,
There are a couple of issues:
1. You are using an old version of jQuery despite the fact that your WordPress is updates. Your theme must be disabling the jQuery version shipping with WordPress and includes it’s predefined and very old one (to be precise 1.4, while it should be 1.10)
2. Your theme is including prettyPhoto script which is also a part of Responsive Lightbox. There might be a conflict too.
I guarantee, that if you solve those issues it will work smoothly.
