Other mistake: When Zach is watching Laney at the show, there are two shots where Laney, Mitch and the little people say, "Be silent, be still". In the first, Mitch's legs are far apart and on the ground, and in the second shot his legs are very close together, with no time to move. (00:22:35)
Other mistake: When Laney goes to the beach she's carrying a huge book. When they leave the beach, there's no book.