After upgrading through Fantastico, an "Upgrader" need to be run.

The first thing this Upgrader may have problem is storage folder ( ../g2data) permission. It asks to run "chmod -R 777″ command. In my case, the FTP progam was not able to run the -R 777 option. There is a php utility in the ../lib/support folder to do the permission change.

What the Upgrader was clear about is this "permission" probelm may have also caused by missing a "version.dat" file in the g2data folder.

There are two lines of text in this file.

1.2.0.6
Gallery-2.0

The first line is the Gallery 2′s core module version. For Gallery 2.2.4, the core module version is 1.2.0.6.