Colorbox plugin freezes Viewport theme

I wanted to use the great Colorbox plugin, but, like many other plugins, when I instal them, my theme Viewport freezes up. I cannot get the two navigation buttons on the front of the site to work and a white horizontile line appears at the bottom of the viewport frame. This has happened dozens of times and I am getting very frustrated.

Is it something to do with jQuery and does anyone have a work-around?