Where are the missing pages?
Traverse Town: Rescue 51 Dalmatians.
Agrabah: Dark Chamber in the Cave of Wonders.
Monstro: Chamber 6.
Halloweentown: The bookcase in the Doctor's Lab.
Atlantica: Ariel's Grotto.
Note that you can find the pages in any order -- the sections of the Wood are unlocked in the same order regardless of which pages you bring back when.