They are unavailable rooms with no map. Attempting to use the Walk Through Walls doesn't enter into any kind of room, instead phasing through the doorway. They just serve as a decoration.
eterna forest, near the eterna side entrance
you have to first obtain the national pokedex, go to the Pokemon mansion on route 212, and talk to the mansion owner,(which is in the left side of the mansion) and different pokemon,(including porygon) will appear in the trophy garden (out back) daily.
impossible. You have to trade it with a pearl user. they are as easy to obtain in pearl as murkrows are in diamond : ) ~Sherry PMMewtwo---At the forest inside the right side door in the Pokemon mansion.
Nothing. You can't go through it unless you have a cheat device. is impossible to get trough
they block it off because they want the game to look cool. there's nothing there.
The north side of Eterna Forest. It's called the Old Chateau. You need to cut down a tree to get there.
NO
you can't
Of course! Try going to www.serebii.net, click on the Diamond/Pearl under the Games on the left side, and find Swarming on the right side of the nest screen. there are 29 different kinds of swarming Pokemon in Pokemon pearl and Pokemon diamond
Just go run around in the mansion just on the side of Eterna Forest.
It is on the left side of the boombox above the white shoes.
Lake Valor side