At the beginning of the movie (when the brothers are in Africa) the text on the screen indicates they are in "Cameroon - Equitorial West Africa", a mis-spelling of the word "Equatorial".
When Sam is extracting the hairs from Toblat's brush, she accidentally drops it, and it lands under the cabinet. But there is no plausible way that it would've landed so far away.
When Gwen drops Derek off, Derek tells her to go to Gale's house. But as the camera follows Derek, in the background the car never moves - it just stays put.