Hi Hafhaff! I'm so glad to hear that you enjoyed the game this much >\\\<
So, about the little box, are you referring to this one, right? I think it's because you need the Silver Key in your inventory, otherwise it will be impossible to react with... the key is in the library on the 1st floor, check the upper shelves until you find the fairy tale book!
(But if you have the Silver Key and this triggered... could you tell me which items you have in the inventory, please? Never say never ;w;)