It’s possible that another script in the site is no longer compatible with the older version of jQuery that the “update” plugin uses. I experimented with the source code on your site and it looks like that by updating the actual lightbox script everything will work. Here’s how to do that:
Go to the plugins section and select Add New.
Search for the WP Editor plugin and install/activate it.
Next go to the Appearance section and select Theme editor.
From the list of files on your right, choose the js folder and then the lightbox folder. Then edit the lightbox.js file there.
Replace everything in the file with this:
Update your settings.
That should update the lightbox script for you. You’ll want to turn off the “update” plugin too. See if that won’t get things fixed for you.