Revealing mistake: In the scene when the main character is in the library on the internet, she goes to a couple of websites. When the shot shows the URL up top, it is C:\windows98\mydocuments\etc.html. Instead of actually searching on the web they used a premade html page and accessed it from their computer.
Revealing mistake: When Rachel is racing to save Noah, she is trying to call him on her cell phone. There is a shot of two hands on the steering wheel as the car turns and then a cut to her holding the phone in one hand a split second later while she was talking the entire time, showing that the shot with both hands was a stunt double and not her.
Revealing mistake: During her research on the video tape Rachel comes across a picture of Anna Morgan drinking champagne with some friends. It's quite obvious that her picture has been copied in. (00:41:25)
Revealing mistake: After Katie pulls the TV plug she tries to find Becca. When we see her from upstairs there's a reflection on the floor next to her that can only come from a ceiling light. However, there's no light falling on her. (00:06:30)
Revealing mistake: After Rachel tumbles down the well, we see her heavy-duty Eveready Commander Flashlight, 12-volt battery and all, bobbing above the surface of the water like a cork. Which is ridiculous. A real 12-volt Commander Flashlight would sink like a rock, because it weighs about 4 pounds. However, the filmmakers needed to explain how Rachel could see at the bottom of a pitch-black well, so they used a lightweight, floating flashlight prop, supposedly providing a light source for the scene.
Revealing mistake: When Rachel searches online for "Moesko Island," you can see in the address bar of the browser that she is really looking at local files (C:\WIN98\Desktop\search.com\... etc). (00:42:30)
Chosen answer: She says "Daddy loves the horses...but he doesn't know" meaning she knows what's about to happen to all his horses. (Because she makes them commit suicide).