Sorry you've had problems.
That error occurs because Roastmaster has lost the "pointer" to the database file. It should not ever happen, so it's a bit baffling. One user reported it happening to him once, but I've not heard of it since. I saw it once on my test unit a couple of years ago, but that instance ended up being a Core Data bug that was cleared with a restart.
If I know why it's occurring, I can tell you how to avoid it. Once the "pointer" is lost, that error will happen every time Roastmaster tries to save data, but nothing will be saved.
Can you tell me what you were doing right before the error happened? The only place where I can imagine something could go wrong would be in the creation, deletion, renaming or switching of a database. What had you been editing before the error popped up?
If it's easier to talk through it, give me a ring on the number in yesterday's email. I'll be up til 11 EST.
Danny