Use Git to get the most current version of the bot. Please use Git if you want to develop plugins, because 0.9 is outdated and will soon be replaced by 1.0.
Grab your copy with the following command:
git clone http://git.otfbot.org/otfbot.git
If you cannot use git or do not want to use git, you can grab the latest git snapshot.
If you try to run OTFBot on Debian Etch you may need this package