A Bringing Up Baby for the Rugrats generation, Along Came Polly updates the classic screwball premise of a free-spirited woman shaking up the well-ordered life of an uptight man. It's just like the Cary Grant-Katharine Hepburn charmer, only with a few minor alterations: Ben Stiller plays a risk assessor instead of a paleontologist, Jennifer Aniston plays a waitress instead of an heiress, a blind ferret replaces the leopard, and, in lieu of the sparkling dialogue, there's a Dolby Digital symphony of pissing, puking, and the deep guttural moans of Irritable Bowel Syndrome. That's to be expected from early-period Jim Carrey, or every-period Jim Varney, but Stiller and Aniston are skilled enough at verbal humor that it's reasonable to hope their first romantic comedy together would have some level of sophistication. But then again, they have a common denominator in humiliation, always playing identifiable straight-men (and -women) who hurl themselves into embarrassing situations and invite viewers to squirm along with them. Writer-director John Hamburg, who also had a hand in the Stiller vehicles Meet The Parents and Zoolander, knows his stars well, but he fatally underestimates his audience, at least those who aren't 11-year-olds. In a movie defined as much by its labored set-ups as by its icky deliveries, the opening reel follows Stiller and new bride Debra Messing through their wedding and tropical honeymoon, where she cheats on him with a French scuba instructor, played by a swishy Hank Azaria (who was presumably paid by the syllable). Still reeling from a calculated risk gone sour, Stiller bounces back when he meets Aniston at an art opening and finds himself attracted to her loose-living ways in spite of his better instincts. After Messing comes back pleading for forgiveness, he assesses the risk of staying with his wife or taking his chances on a flaky, promiscuous commitment-phobe who's into salsa dancing and stomach-churning ethnic food. Hamburg tacks on a couple of time-filling subplots, including an amusing turn by Philip Seymour Hoffman as a long-in-the-tooth Brat Packer who takes a role in a community-theater revival of Jesus Christ Superstar. With a cast this gifted, some of the throwaway jokes stick, but when Along Came Polly goes for its biggest, grossest laughs, the strings show well in advance. (Apropos of nothing, Aniston mentions the $200 she paid for a Swedish loofah; a few scenes later, what does Stiller reach for when the toilet starts overflowing?) But in a genre rarely geared toward men, remorseless slobs can cherish their own romantic fantasy: Sixty years ago, women swooned for suave gentlemen like Cary Grant. Now, Prince Charming can have a weak bladder.