It's mentioned in several places (usually in the context of the missing disk).
Help to rediscover another unknown Ami game!
is most likely the thread you're talking about (as far as I can tell the one where it's first mentioned).
Originally Posted by Bobic
The game (the one which is technically better than Lionheart and has this "uncrackable" copy protection) is called "Dämonenburg" (english name: Demon Castle). More news about this game and the process to rescue it will follow in the next weeks.