Continuity mistake: When Alexandra Rover is about to leave the apartment to go and help Nim, she is standing in front of the door debating if she can go or not (she is agoraphobic, afraid to leave her home). Notice that the baby chain is hooked to the door. Alex Rover (the imaginary adventure hero) is leaning against the wall telling Alexandra she can and must go help Nim and that she must turn the door knob. In the next scene, Alexandra turns the knob and opens the door. She never unhooked the baby chain, and Alex Rover is an imaginary character so he could not have unhooked it.
Continuity mistake: When Alex reads Nim's first e-mail reply, there's an extra sentence ("He'll be back on Thursday") that Nim never wrote.
Continuity mistake: After Fred the lizard 'peeked' below the microscope Jack was using, he suddenly appeared a foot away from the microscope when the camera changed angles.
Continuity mistake: About halfway through, Gerard Butler is on a boat watching a whale go by. He is holding a large sextant and as he watches the whale, he moves the sextant so that it is vertical and behind his knee. The shot changes and the sextant has instantly changed to being held horizontally on his knee.
Answer: Generator. It's shown several times during the film.
Brenda Elzin