Continuity mistake: When Rex announces that his program costs, "Only $300," Kip's hands go from being on the ground to in his lap.
Continuity mistake: When Napoleon shows Pedro the picture of his "old girlfriend", the position of his fingers on the picture changes between shots.
Continuity mistake: When Pedro returns to school after being sick, Napoleon sits next to him in the cafeteria. There is a piece of food on the table next to Pedro's lunch tray, and in the next shot it's gone.
Audio problem: In the last scene before the credits, Napoleon and Deb are playing the ball game, and when they high-five each other at the end, it is out of sync.
Continuity mistake: When Pedro and Napoleon are shopping for a suit for Napoleon to wear for prom, the tie knot is wide and makes the tie look wide. At the dance, Napoleon's tie knot changes and looks thinner on top, and the tie looks thinner also.
Continuity mistake: When Kip and Rico go bowling, Kip bowls and there are bumpers on either side of the lane. In the next shot the bumpers are gone.
Continuity mistake: The first time that Napoleon is seen walking out of his house to feed Tina, the front steps are in bright sunlight. When he returns a moment later, and Kip is lacing his rollerblades, the steps are covered in shade from a nearby tree.
Continuity mistake: When Napoleon is counting up his money, his watch moves further up his wrist between shots.
Deliberate mistake: When Napoleon asks the school secretary if he can borrow the phone, she pushes the phone toward him but in the shot of Napoleon you can see the phone never actually moved from before he asks to borrow it to the time he makes the call. This is only seen on the full-screen version of the film. The phone is not visible on the wide-screen version because the bottom portion of the image is cut. (00:07:00)
Continuity mistake: When Deb gives Napoleon the picture of the girl, the position of the picture in Napoleon's hand changes between shots.
Continuity mistake: When Kip runs over the plastic bowl to demonstrate its strength, watch the location of the left rear tire's valve stem. In the close-up when Kip wedges the bowl behind the tire, the valve stem can be seen near the top of the screen at the 4:00 position. When Kip walks to the front, but the van hasn't moved yet, the valve stem is now at the 7:00 position.
Continuity mistake: When Napoleon is giving Trisha's mom the dance invitation you can see a car in the reflection on the door. Then when it shows the door again the car is gone.
Continuity mistake: When the uncle and Kip are eating at the restaurant, the uncle's onion rings continuously change position between shots.
Continuity mistake: When Deb comes to sell handycrafts to Napoleon, she has three boxes: a blue one, a red and white one, and a teal one. When Napoleon leaves his house he only has two boxes. But when he gives them to her at school, he has all three.
Continuity mistake: When Kip and Uncle Rico are in the diner, Rico's onion rings keep changing position.
Chosen answer: This is never explained or referenced.