Foogallery: Images open full-size in new window instead of lightbox

I loaded the foogallery plugin and the foolightbox plugin. At first all worked fine and now suddenly the lightbox view does not work anymore but only opens the full size images. I deleted the plugin and reloaded it, I tried the JSoptimization but nothing has worked so far.
I would really need this to work properly with the Sydney theme.
Help please?

Hello,

Can you please provide a link to your website?

Kind Regards, Roman.