Character mistake: During the meeting between Langdon, Sophie and Sir Teabing, Teabing refers to Scatoma as "the mind seeing what it wants to see." Scatoma refers to a partial loss of vision. He probably meant to use Pareidolia, which refers to seeing patterns that are not really there.
Character mistake: Langdon points out that the Templars were slaughtered on October 13th, 1307, and Sophie comments, "Friday the 13th", implying that this is when the fear of Friday the 13th originated. In reality, fear of Friday the 13th didn't really begin until early in the 20th century.