Is this a fresh install or an update? If it's a fresh install how was it done? if it was an update did you replace ALL files except the config.inc.php ?
Personally I'm against the ability to edit the templates via the admin as I see it as a security risk. I always recommend downloading the file using an FTP client and editing it on your system or get a text editor like PSPad which can edit the files on your server via FTP.
From reading the error it sounds more like a problem with the database and not the script. Any other scripts using MySQL and if so are they erroring as well? Contact your host about it.
CPenal has apparently seriously messed p in the latest version and 2.3.3 is not installing correctly. Simply download it from this site and replace all your existing files except the config.inc.php
Turn on password for comments in Admin - General Settings
-----------------------------------------------------
Schalten Sie Kennwort für Anmerkungen in Admin - allgemeine Einstellungen ein