Other mistake: When in the Mayan temple Flynn pools out the book. It is completely intact and the pages are flat and even. A book which has been under water for a long time (during their swim) would not look like that.
The Librarian: Quest for the Spear (2004)
1 other mistake - chronological order
Directed by: Peter Winther
Starring: Kyle MacLachlan, Bob Newhart, Noah Wyle, Sonya Walger
Factual error: Flynn says that the chamber in the Mayan temple is 300 quahuitls long. A quahuitl is approximately 2.5 meters, so 300 quahuitls would be 750 meters, or nearly half a mile. The chamber he and the others are in is large, but not that large.
Flynn Carsen: Professor Harris. I should've known he was evil. He gave me an A-minus.