Continuity mistake: There is a scene where the Chipmunks and Chipettes are singing the song "Girls of Rock and Roll." In that scene, it shows the boys walking up the stairs together and from left to right the order is: Simon, Alvin & Theodore. The shot goes to the girls then back to the guys. The order of the guys has switched: (left to right) Theodore, Alvin & Simon.
Continuity mistake: When Valerie Vomit is about to steal the Pepsi truck, we see the driver standing behind the truck. In the next closeup we see a cord attached to his pants and the truck, which, as a result, rips his pants off as Valerie speeds off with the truck. Yet in the shot previous to this, there was no cord attached to his pants or the truck. (00:29:20)