stamps for the mirror

I have all but one stamp. I don't remember what rooms had the stamps and which ones I had. how can I find out

Have you checked the walkthrough?

YES, I have the same problem, I am missing the TOP RIGHT STAMP. I checked the journal and walk-through, but yielded nothing, so I went again through all the rooms, but nothing.
the hint says nothing left to do in room. what now?????

have you finished the dancing dolls yet?

I have the same problem. I have 5 stamps on the mirror which is what the walkthrough shows. But I still can't go through the mirror. Can someone help me.