So I noticed this happens quiet a lot for me. It seems very random. I'll go into the symbol that transitions you to the next floor, the screen goes black, the BGM still plays, but the screen never transitions and stays black.
I have to close the game and open it again, and all my day's progress is gone of course.
I will have to enter the dungeon again and hope it doesn't happen.

anyone else have this problem?

Don't have this problem,but are you playing full screen or windowed?
Try playing windowed or full screen,there is a custom file in the recettear folder try changing some settings.
Or update drivers for your graphic card.
Anyway you didn't say what kind of OS you are using or system.

I don't know if this is even needed but are you using any codecs?
I do use combined community codecs package.
Last thing you could do is install directx 9.0c redistibutable if you haven't done that.
Out of ideas now.