Character mistake: The newspaper article states that Lucinda was thirty-three at the time of her death in 1988. However, that would make her just four years old when she wrote the time capsule note in 1959 - four years old in the 3rd grade?
Character mistake: In the film, five items are stolen: the Magna Carta, the Turin Shroud, the Imperial Sword of Japan, the Pope's ring and the Pink Panther diamond. When Alfred Molina's character is challenged that they had found everything but the Pink Panther, he protests that 3 out of 4 is not bad, that's 75%. In fact, they had found 4 out of 5 or 80%.
Character mistake: In a shot that flashes by very briefly, a London newspaper's headline is shown: "Sherlock Holmes Aides Police." "Aides" should be "aids".
Character mistake: When discussing the new Pope's name (Luke) at the end of the film, Langdon says: "There have been many Marks and Johns, but never a Luke." In fact, though there have been 23 Pope Johns, there has only been one Pope Mark - reigning for 9 months in 336.
Character mistake: The word "satellite" on the uplink screen at which Sam Rockwell spends a lot of time staring, is incorrectly spelled "sattelite". The correct spelling is used a little further down on the same display.