Ray, download the newest version and follow their upgarde procedure. I've used it on a gallery embedded within PostNuke, and 2 galleries in Ibays and it's worked just fine.
In a nut shell, backup current gallery, gunzip new version, untar new version, copy to gallery directory, over writing old files. Enable configure mode, run setup, disable config, visit the gallery. The first gallery you go to will present you with an option to upgrade all galleries, do that once and all galleries will be done.
Mine took about 10 minutes to run through the upgrading of the galleries (above and beyond the time it takes to tar all the files for backup).
Easy & Simple, just the way I like it.
Terry