Continuity mistake: While Tori is getting her mask removed, another shot shows her sneaking back on stage, but the next shot shows her still getting her mask removed.
Audio problem: When Tori is on the stage singing, Robbie walks up to Tori and says "I deserve it!" When he says "ow!" his lips don't match.
Answer: The Director hated working with Melinda, but knew that her superstar popularity and status would get his movie a big buzz and higher ratings. And the movie was discontinued for a re-audition to fill-in Melinda's leading/major role.