Trying to produce the second of two novels with Simon & Schuster - with which she has a seven-figure deal - Weisberger apparently has a case of writer's block. Lowdown hears that Vogue editor Wintour's 29-year-old former assistant - whose thinly veiled first novel, "The Devil Wears Prada," lampooned her ex-boss and sold more than a million copies for Doubleday - is in agony over her book-in-progress, which her editor has allegedly advised her to trash.

A Lowdown spy claims: "She actually wrote several chapters, but she was basically told they sucked and she has to start over." Weisberger, meanwhile, has apparently been trying to put the best face on the situation, telling friends she has yet to begin the novel. While "The Devil Wears Prada" was a rousing commercial success - scoring the author a $200,000 movie option for a Meryl Streep vehicle that will be released this summer - Weisberger's next novel, "Everyone Worth Knowing," earned declining sales when it was published last year.

Neither Weisberger's agent, Deborah Schneider, nor Simon & Schuster would comment on Weisberger's rumored troubles. But Wintour spokesman Patrick O'Connell couldn't resist gloating. "Maybe she should get another job as someone's assistant," O'Connell sniped. Meow.