Instead, be afraid of Katie Holmes trying to act
What an incredibly poor movie and a waste of money this was. In order for a scary movie to properly work, the audience must have an emotional connection to the main characters, or the characters who are being subjected to the horror. Don't Be Afraid of the Dark fails at this miserably. A little girl is the main character and she is spoiled, stubborn, obnoxious, ungrateful, etc. She brings on all of the bad things that happens to her, her father (Guy Pearce), and her soon to be step-mother (Katie Holmes). So, when her actions create the horror situation, we, in no way, shape, or form, do not feel sympathy for her.
The soon-to-be step-mother role is meant to be the heart of the movie. This character has the most development, and is positioned to become a hero in the end. Unfortunately, Katie Holmes was cast in this part. Holmes is not completely untalented, as I quite liked her in Thank You for Smoking. But here, she is completely wrong for the role, and she does not develop a relationship with the audience.
The father role, played well by Guy Pearce, is initially the movie's hope at creating the emotional connection. Typically, the distant father, would be cruel, disinterested in his daughter but the film portrays him to be entirely committed to making his new family situation work. Then the story pulls the rug out from under the character as he is portrayed to care more about his financial investment then his daughter. Katie Holmes is meant to take his place as the character we connect to, but as I previously discussed, she fails.
Guillermo del Toro is credited as a co-writer on this film, but if you want to see a truly great movie about a young girl surrounded by scary creatures, buy his magnificent Pan's Labyrinth.