Sorry for the delay, I finally had some time to dig into this, and it’s a good thing I had time, because it took all evening. I think what happened is some bad .po files got checked in, which has been keeping the gettext tools from working properly. I imported the latest batch of .po files from launchpad, so based on those a:
make LANGUAGES
or
make LANGUAGES=de_DE
Should create fresh .mo files, which cataclysm should then start using.
There was also an issue with some code that tried to use language specific names for game worlds that was causing a crash, but sounds like you didn’t hit that one.