Factual error: When the roast ox is cut in half by the swordsman, fruits spill out which were totally unknown to the ancient Greeks - most notably pineapples, mangoes and papayas. None of these fruits were available to Europeans for another 3,500 years when they were discovered in South America and the South Pacific. (And Greek explorers did NOT discover them independently, nor did they trade with anyone who did.).

Continuity: In the scene when the dwarves find the invisible barrier. Wally takes the map from Randall and calls him crazy. Randall then picks up a skull and throws it, shattering the invisible barrier. At this point Randall takes the map back from Wally, then the camera angle changes and we see Randall taking the map off Wally again.

Audio problem: When Kevin and his crew of thieving little people land in the Middle Ages, Randall informs Kevin that they made all of what's surrounding them, trees, shrubs, bushes etc. Kevin's reply is "Phew, that's not bad" He says this without opening his mouth. This was looped into the film later on.