Wow, 6 minutes. Thanks for the super-quick reply.
--I didn't realize I was supposed to manually add the $cookie_domain variable. I will do so.
--I will start with the 4.0 upgrade script. Thanks for clarifying.
--I am still assuming that the data directory does NOT get uploaded for an upgrade, as it would overwrite my current data directory. Or should I be running the upgrade script from a new directory (ex: mysite.com/gallery2) with the new empty data directory in place? UPGRADE.TXT says to upload all files except config-inc.php and install.php.
Thanks again, sorry for the obtuseness -- I want to do this upgrade perfectly.