Character mistake: Arthur (who knew him) says that Cary Grant was from Surrey and Iris (who is from Surrey) agrees with him. Cary Grant was actually from Bristol.
Character mistake: When they arrive at the motel, the mother says that the grandpa is in room 13, but when he opens his door it is room 208.
Character mistake: When playing Alex's game for the first time, the buttons Grandma presses are different to the buttons Alex describes. For instance, she presses the 'punch' button to use a spell, when she should use the left trigger.
Character mistake: When the coach is eating a sandwich in the locker room, there is a headline in the paper he's reading that says, "Diamond Backs rattle Timber Wolfs..." Diamondback is one word and the plural of wolf is wolves. (00:45:00)
Character mistake: Before he scampers inside to spy on the humans, Claudius tells the other animals, "I'm your mouse on the inside!" Maybe he should check a mirror while he's in there. Claudius isn't a mouse - he's a rat.
Character mistake: At the very beginning, when Haley is in court, the cop says that the property damage from the previous scene looks to be about $14,000. Although we can't expect a cop to know the true cost of the property, the only things damaged were the large window and maybe the metal framework supporting it. The window couldn't be any more than $1000.
Character mistake: Ashley should be smart enough to know not to wear high heels while buffing the bowling alley lane. They might break or scuff up the floor, she should've worn sneakers or sandals.
Character mistake: When Bob Munro (Robin Williams) is behind the tractor, the speedometer shows that it is below 10mph. He then states that they are going twelve. How could he if they didn't reach 10mph yet?
Character mistake: At the end of the movie, Darryl tells Calvin they don't have a back door. There's a back door in the kitchen and another door that goes back to the backyard patio.
Character mistake: Lucy says the source of the quote "To err is human" as Alexander Pope's "An Essay on Man." The quote actually originates from Pope's earlier work, "An Essay on Criticism."
Character mistake: When Gwen Piper is talking to Aggie in the soup pot at the beginning of the movie, Aggie addresses Gwen as Linda.
Suggested correction: Aggie says Gwen darling.