If you update you also should update the other files like the root index.php (in this case nothing was changed there but to be sure...)
There was another problem with next/prev that has been fixed after the nightly was generated. So please either wait until the next nightly or use the svn version directly.
Ok, 11th June nightly build still does the "next image is sometimes next album's image" problem but it stopped doing the weird "back" is "next". Search http://development.thepaperdump.com/dump/ for "computer city".