Rapair a Javascript Error on Prestashop website (seems to be a incompatibility with any module)

On [login to view URL] Fancybox (and other javascript) errors. Seems that fancy working on homepage. Slideshow works on home but no when you click on a product. Perhaps some module incompatibility? For example, about fancybox: 1-Read Terms, on finalize an order, don't see the box to check. (I repaired modifing code meanwhile) 2-If you click on image, it opens on a other page, and you may do click "Return" navigator button to return to website instead of close button on fancy box. I attach snap On this website you can see how fancy box works, when you click on image: [login to view URL] 3-Slideshow don't change the images (before works good changing different images automatically). Perhaps a conflict with any module?