Continuity mistake: When Peter is talking to his editor after the first time Sarina out-scoops him, he's holding a newspaper under his arm as he walks up to his editor's office. The shot switches to the editor and when it turns back to Peter the paper is gone.
Continuity mistake: When Peter is in the diner showing Sabrina the picture he puts the picture down and walks to get coffee. As he gets up Sabrina is reaching for the picture and the camera shows Peter asking her if she wants a doughnut. The camera pans back to her and she is reaching for the picture again - it is not in the same place it was a moment ago.
Revealing mistake: In the scene where the dead guy falls out of the closet and he and Julia fall to the floor, the dead guy moves (especially his legs) when Julia gets up.
Continuity mistake: At the end, when the film slide falls out of Peterson's pen it's all rolled up, but seconds later when Peterson grabs it it's perfectly straight even though no one had touched it.