Continuity mistake: When the group are in the diner and Garth notices his "dream girl" stacking plates of pie and cake in the display case, she can be seen placing a plate on an empty tray, then the camera returns to Garth. Moments later the camera is returned to his dream girl and the tray is again empty. (00:10:05)
Audio problem: At the loft party, while Cassandra is singing the song Touch Me there is a moment where Wayne turns to the camera and says "God, she's amazing." While Wayne is saying this the audio track plays an extra beat which throws the track out of sync just as Terry walks up to Wayne, causing Cassandra's mouth to not match the lyrics.
Audio problem: When Wayne plays the "May I help you?" riff on the black guitar to get the clerk's attention, he ends the riff by manipulating the whammy bar. However, rather than the "scooping" sound that comes from manipulating a whammy bar, the sound heard is actually trilling (rapidly alternating between two or more notes on the same string).
Continuity mistake: After Wayne is finished using the cue cards for Noah Vanderhoff's interview, they cut to commercial. Wayne grips the stack of cards with two hands initially, but when the shot changes to Terry saying, "We're at commercial," Wayne is only using his left hand. (01:07:50)
Deliberate mistake: When Wayne begins playing the "Excalibur" guitar, the clerk stops him and directs him to a "No Stairway to Heaven" sign. The problem is that the guitar riff Wayne started playing sounded nothing like "Stairway to Heaven" so the clerk had no reason to interrupt him. Evidently the intro to "Stairway" was actually played in the theatrical version of the film, but its exclusion in the home video release makes the scene rather dubious.
Continuity mistake: When Benjamin is talking to Wayne and Garth about giving Vanderhoff a spot on the show in the first scene. On the left side of the end of the table there is a tray of nachos with dip and different kinds of drinks, then in the next scene when Wayne talks to Garth about selling out the nachos with dip are on the right side of the table and the drinks are gone. (00:47:47)