The rejection letter in the opening shots from DMG Publishing House is dated February 29, 2007. Obviously that date does not exist in our world, as 2007 is not a leap year.
The Director credited on the movie poster is "Alan Smithee," a fictional alias sometime used when a director has asked that his name be removed from a film he no longer claims.
The number on the door of Rob's room in Highberger House is 217. This is also the number of the notoriously haunted hotel room in Stephen King's novel The Shining.