Shooting schedules are important so that you are organized and everyone knows when they are needed to film. Without shooting schedules, people may turn up to film at different times and therefore no filming would be completed.
Location release forms are important so you can get permission to film in certain places without getting into trouble. If you do not get permission to film somewhere but do it anyway you could be sued or arrested etc.
Budgets are important as it tells the filmmaker how much money he needs to make the film. Without a budget the filmmaker wouldn't have an idea how much he needs and therefore might not get the amount of money he needs.