thanks a lot. That was really insightful. I didn't use babel for several month and I always struggle to get into it again.
I clearly was confused about the variable definition. Using a function like I did, one has to do it basically twice, once for babel and once for the target language. I never used the sbe-macro (Actually, I was not even aware of it). Thus, I thought the problem was somehow there.
Furthermore, I missed that I should at least call the function once ;)
Would it be possible that the error-message contains more infos? E.g. some hints within the mini-buffer or *Messages*-buffer. That would make it easier to debug what is going wrong.