Deliberate mistake: The atmosphere on Mars is only 1% as dense of that as Earth, so 175kph windstorms would feel like a light breeze. They would have very little effect on the astronauts or MAV. The writers of the book and the film were aware of this, it was a small cheat to let the rest of the story unfold.
Deliberate mistake: The little red-haired girl boards a bus with other children who are headed to summer camp. As the bus drives away, there is nobody in the driver's seat. This movie maintains Charles Schulz's policy of never showing adults in his comic strips or animated television specials, but a bus driver could at least have been depicted in silhouette.