The building you want to go into is the one with the three portal candles. If you've already fought Fushiko, you don't need to light the candles again (which summons the enemies again); you can just access the book "A New Beginning".
Be sure you're trying to get into the right building. Traveling to the southeast part of the map, the building is at the end of the far southwest branch of the roads: the one closest to the picture of the large pig in a purple coat.
If you can't get into this building, go see Wei Pei in the village. If he has nothing for you to do, and you still can't get in, send in a ticket to Support.