lightbox gallery breaks my site

Hi there, i am using this AJAX based theme http://themeforest.net/item/john-smith-ajax-portfolio-wp-theme/4199227

and want a image lightbox to be used with the [gallery] shortcode, however when I install this plugin, none of the pages appear to load. Could this be that I have installed it wrong, or that the plugin is incompatible with the theme? In either case, some assistance would be hugely appreciated, thanks!

http://wordpress.org/plugins/lightbox-gallery/