Sorry Raze for replying so late, I did not notize I had gotten an answer (actually had decided to think that no one was active on here anymore :x)
I think for my broken quest: The actual reason might be that I bought an old CD version of the game? Because I never had this problem (or the one with the cow-thief disappearing, or the one with Markus lost delivery quest breaking, ...) with the Steam version. I just bought the CD because I am no longer using Steam - now I sure got to appreciate the service of automatic updates and patches!
That said, I just played through the game without Ben's beer. Sorry, Ben :<