For Warner Bros., fielding its first PG-13 Potter picture, the encouraging news is that Rowling's fans made this segue into Harry's angry young manhood en masse back in 2000, thanks to a novel that marked a bravura leap in ambition (and size, nearly twice as long as any preceding installment). Yet the worrisome news for Potterphiles is that adapting Rowling's fat, beloved opus has made for the greatest challenge Hollywood's Pottermakers have ever faced. Director Mike Newell (Four Weddings and a Funeral), the man at the epicenter of Goblet's transition, understands the stakes. ''Of course I'm worried! We're talking about a passionate fan base. I won't know if I've pleased them until I put the movie in front of them,'' says Newell. ''Now that will be a very freaky occasion.''