Takashi and Yoshiki,
One other possible bug in the Demon Castle (caused by me): On the page with the right button (page 3), there is a transparent shield over page. Please verify that both the go back and go forward buttons work. They need to be on top of the shield. Also make sure the shield is marked "cannot be picked up".
Another thing to fix is the sentence along the bottom (below the book). It says "(To exit, click on Navigator below, then click PREV.)". Instead it should say "To exit, click the [<] button above." (insert the icon for Prev Project in the sentence)
--Ted.