I have just failed miserably at upgrading the gallery to the latest (2.3.1) version of Gallery. I didn't bother with debugging very much, but I guess the PHP 5.3 upgrade broke something, which resulted in an un-upgradeable installation of Gallery. I did try reinstalling it with the old data, but that just broke it completely. The new Gallery 3 is approaching it's release, so an overhaul of the three-year-old installation would likely have been expected anyway. Until then, the gallery remains offline.