Other mistake: In episode 4-14: "Krypto," Genevieve tells Jason that the heirs of a 17th century woman named Gertrude are in danger. She then tells him that they themselves are "Gertrude's ancestors." But she must mean descendants, which means the opposite of ancestors.
Continuity mistake: Clark goes to see Lex about the dog. Lex, who was about to start a game of pool, breaks a fresh rack. Lex then goes to make his second shot from near the side pocket and as he does you can see there are two striped balls near the rail close to Lex's cue stick. Just after he takes his shot those balls are gone even though those balls had not been hit.
Continuity mistake: After Krypto comes around the fence we hear one of the two guys say "You got all the bags out of the truck, right?". The camera then pans over to the van and you can see, under the rear of the van, two gas containers. There is a metal one on the left and a plastic one on the right. Krypto starts to run for the truck and we see the containers again only now the metal one is on the right and the plastic one is on the left.