Revealing mistake: In the swimming pool scene between Annette and Sebastian, a positioning mark can be seen quite clearly on the floor. [The swimming pool used was freezing cold, about 40 degrees, so Ryan Phillippe and Reese Witherspoon were freezing (look close and you can see Ryan shivering), and so were the camera crew, that they didn't repeat the shot, so the positioning mark was left in.]
Continuity mistake: In the final scene where Annette is driving the Jaguar and having flashbacks, watch as she drives past lovely rolling hills and pastures. Cut to a helicopter shot of her driving the car along a New York freeway (FDR I think...) This mistake has been confirmed by the director.
Question: Maybe I'm just missing something here, but when Kathryn and Annette talk in the bathroom, why does Kathryn act as though she doesn't know Annette? She obviously knows who she is as she has seen her several times. We know why Annette pretends not to know Kathryn but this bit doesn't make sense.