I upgraded from 2.2.3 to 2.2.5. When I log in to /mailuser it seems that a user no longer can change the prefered language. It shows "nl" and doesn't change to Dutch. Interestingly enough it does change to German when selecting "de" EDIT: I uploaded the dutch language pack that Hans made available and it's solved
If others also have the described problem: The last version of my Dutch language pack is released on 04-08-2006 and can be downloaded here: http://ispconfig.bb-hosting.org/downloads/language_nl.pkg It can be installed by using the update manager within ISPConfig. This version is also updated in the SVN Repository, so it will be available in a near future release, which means there will be no failure anymore.