Need to remove #nimblebox[nimble_portfolio_gal_default] from your URL?
in prettyphoto.js, change
(function(j){j(document).on('nimble_portfolio_lightbox',function(event, obj){obj.items.prettyPhoto();})})(jQuery);
to
(function(j){j(document).on('nimble_portfolio_lightbox',function(event, obj){obj.items.prettyPhoto({deeplinking: false});})})(jQuery);