Revealing mistake: When Mrs Arness and her dog, William Shakespeare, are at Peter's house, the dog walks over to Georgey. You can see the actor who plays Georgey had to hold dog treats in both of his hands to keep the dog near him in the scene. Confirmed in the audio commentary. (01:09:05)Super Grover
Deliberate mistake: It is not believable that Charlene, the dangerous prison escapee, would seek legal assistance to re-open her case, and not be concerned about escape charges, in addition to freely being seen by many people.
Continuity mistake: At the end of the movie in the scene where they are moving into the new office, Peter is talking to Charlene at his desk. Behind her there are three books stacked in a certain order. Later in the scene when he is talking to his wife the books are stacked differently. (01:37:40 - 01:38:45)
Visible crew/equipment: When Peter is going home to get ready for his "date", he goes to get wine out of the fridge. If you slow down on the DVD you can see part of the camera and a man in a pink shirt standing next to the camera operator (director Adam Shankman?).
Revealing mistake: During the fight scene between Charlene and the girl, as Charlene hits the woman it is visible that she does not even touch her.
Continuity mistake: When Peter catches Georgey reading the adult magazine, Peter says to Charlene, "I'm turning you in." At this point in the movie Peter doesn't know she escaped, so there would be no reason to turn her in.