Lightbox (videobox.js; mootools) not working in Firefox for both Mac and PC

First off, thanks for any help with this.

I have jCarousel sliders setup that has users click thumbnails to get a pop up video box (the pop up videobox is done using a script called videobox.js found here: It works fine in all other browsers, but clicking one of the first three thumbnails on the horizontal slider in Firefox opens the video in a new window and/or has a broken link (if you scroll to the next three thumbnails, videobox works correctly oddly enough). Again, I only have this issue using Firefox. Thoughts?

Here is the site with the sliders (horz and vert):