It seems to have been an incompatibility with the xf86-input-evdev-git package. Installing the package from the repos lets it work.
PPA for GfxTablet available
I’ve just finished my first foray into Debian packaging, and hence a PPA is now available at http://launchpad.net/akdor1154/gfxtablet. You can add it to your Ubuntu system with
sudo apt-add-repository ppa:akdor1154/gfxtablet sudo apt-get update sudo apt-get install networktablet
It’s identical to what is in rfc2822’s master repository. Currently it needs to be run as root (or else grant your user access to
/dev/uinput) but I intend on fixing this.