Comment 9 for bug 999155

Gosset, there are a couple of options until the translation is updated:

Try temporarily running with the English or Spanish user interface:
$ LANGUAGE=en onboard
$ LANGUAGE=es onboard

or, disable the catalan translation (will be restored when language-pack-gnome-ca-base is updated):
$ sudo mv /usr/share/locale-langpack/ca/LC_MESSAGES/onboard.mo{,_}

or get the latest Onboard from our PPA, quoting Francesco:
"You can find Onboard 0.97.1, that contains the fix to this problem in our Stable PPA for oneiric, precise and quantal: https://launchpad.net/~onboard/+archive/stable"