Character mistake: Dexter says "Aconagua" is the highest point in South America. The name of the highest mountain in the Andes is "Aconcagua".
Continuity mistake: As Dexter is driving back from Marshfield after picking up the computer part, he is trying to figure out answers to a sample test. There is obviously a window on the driver's side - there is a reflection in it, and he has also taped several pieces of paper to it. When he arrives at Medfield, he climbs out the side of his dune buggy, indicating that there is no window.
