Without going into detail about the error (I can't say much about it)... what I would try in you situation:
* To bring your site up again, I would uninstall the ODT-Plugin by deleting /lib/plugins/odt (I think missing ODT export is less critical than a not working wiki).
* If everything works after deleting ODT, I would upgrade *manually* to 2011-05-25 (see below).
* Make a backup and try to re-install the newest version of ODT. If everything works then, your former ODT plugin version probably was too old. Many users forget about upgrading their plugins from time to time.
BTW... Why do you use installatron for updating and/or install DokuWiki? A very easy upgrade is one of DokuWiki's killer features:
* Just overwrite the existing DokuWiki directory on your webserver with the unpacked newest realease via (S)FTP.
* Delete unneeded files:
http://www.dokuwiki.org/install:upgrade#files_to_remove. Example if you updated from 2010-11-07 to Rincewind rc2011-04-21 you should delte "conf/words.aspell.dist" and "lib/styles/style.css"
* Check for plugin and/or template updates. If you installed your Plugins with the plugin-manager by using an URL, a simle click on "Update" is enough.
* What can be easier? Ok... the
Upgrade plugin... You might give it a try on a test installation to see if everything works with your hosting provider.