[Mediawiki-l] MediaWiki-Messages (Namespace Mediawiki:...) in wrong language

[2036 at gmx.de]

Hello!

I have a MediaWiki-Installation since 1.4x, now running at 1.6.8.

Some of the MediaWiki-Messages now appear in english, although my wiki runs in german 
language.

I searched for some of the english phrases in the Mediawiki: Namespace, and corrected 
them manually. But there are still many messages in wrong language ... what's wrong?

Why they appear in english?
How to switch all Mediawiki:messages to german?

Regards,
Jan