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: When young Alan is talking young Sarah, he says that he found a board game at the factory. Alan didn't find the game at the factory. He found the game across from the factory at a construction site.
Character mistake: In the scene when they do the weigh in, the camera man recording Ben does not even have the tape door pressed into the camera, so nothing is being recorded.
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: When in the mineshaft Trevor says that magnesium is used in gunpowder. That is not correct.
Character mistake: When Barb introduces herself to Flint, Steve calls her a monkey, and she corrects him saying that she's an "Orangutang", pronouncing the G at the end. But the correct word is Orangutan, with no G sound. Barb would surely know this, as a genius ape.
Character mistake: Near the end of the movie, Charlotte says she doesn't have the strength to climb down into the crate. Two seconds later, she climbs down to comfort Wilbur, then climbs back up. Even if she couldn't go all the way to the crate, she was low enough that Wilbur could have carried her there himself.
Character mistake: When looking at the newspaper about Chester Copperpot, the caption under his picture reads, "Reclusive scavenger claims, 'I have they key.'" It should read "I have the key."
Character mistake: Before the junk man drives away he calls Mr Coggins "Bill." The correct first name is George.
Character mistake: At the ravine, upon learning that the bridge doesn't exist yet, Marty states to Doc "We can't wait a year and a half for this to be built". If you carefully look at the sign, it says the bridge is opening Summer 1886. That's under a year away, not a year and a half from Sept. 1885.
Character mistake: After Santa gives the children new clothes, Ray says that he and the mother can now raise the 9 children. The mother points out that they only have 2, but he points to the group of orphans to include them. However that makes only 7 children.
Character mistake: When Mike fights by the concession stand at the mall, the Reuben sandwich is misspelled on the menu in "Rueben." (00:06:35)
Character mistake: Big Ben is loaded feet first into the ambulance, he should've been loaded head first.
Character mistake: The professor identifies the "sea monsters" as plesiosaurs from the Pleistocene. Plesiosaurs became extinct at the end of the age of dinosaurs, nearly 60 million years before the Pleistocene. Of course, the Loch Ness Monster might be an exception.
Character mistake: When Marian is correcting Amaryllis for the girls' poor grammar in saying "can I" instead of "may I" over the cross-hand piece, the girl then asks if she can go play that cross-hand piece and Marian replies, "now you can play your cross-hand piece."
Character mistake: The sign outside the Fortune Teller's tent says "Madame Zaza", but when Droopy enters the tent, Spike introduces himself as "Madame Zazu."
Character mistake: Mitch and Hecky are experienced ranchers - so why, when they are all camping, would they leave all the food out in the open within easy reach of bears and other wildlife?
Suggested correction: Is this in reference to when Vicky throws the food everywhere? Mitch is obviously already up and about in this scene as he is wearing shaving cream. That may be food he has put out for breakfast for when everyone else gets up.
Character mistake: Sabrina calls checkmate but the board is not actually in a checkmate position. (00:55:15)
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: Mr Potato Head gets torn apart by baby Molly after the opening scene. When Andy returns to the room with Buzz everyone resumes their positions, but Mr Potato Head looks for his bits and sits under the shelf with the other toys.
Suggested correction: The construction might very well be part of the factory, a new factory building for example.
lionhead
The sign at the construction site said it was an "Executive Office Annex" that they were building.
Bishop73
Even though the sign said it was an Annex, construction was still being done outside of the main factory where Alan found the game. Not inside of the main factory itself.