Theme breaking lightbox plugin

We have a customized child theme
on our site

It was created by another web design firm and apparently they totally screwed it up. For some reason, I’ve laways had lots of problems with any lightbox, shadowbox, auto thickbox, prettyphoto, etc player. I can never get them to work in the pop-ups, as if the plugin isn’t working at all.

Once I switch to an older theme, they always work fine. What is it about my custom theme that is breaking these lightbox plugins?

An example would be on This page. The Click Here link at the top should open the pdf you see within the lightbox, but it doesn’t.

I am completely perplexed. Any help would be very gracious.