Continuity mistake: As Sam is preparing to go on stage as Don Quixote, after catching the lead actor, a quick cut to Dulcinea dancing is shown. It is supposed to be Sam's love interest and ex piano teacher Nicole as Dulcinea. However, you can see Nicole standing in the background, in the pink outfit she was wearing in scenes from the beginning of the episode.
Character mistake: In the preview for this episode, Charlie has trouble getting his countdown straight. He shouts that Sam is on in 50 seconds, then 47, then 48. In the episode itself, the mistake is corrected with a rather obvious overdub, changing the final number to 43.