Sarah Jessica Parker admitted to a few nerves as she and Harvey Weinstein gave VIPs a sneak peek of footage from their upcoming picture, “I Don’t Know How She Does It,” in Cannes Friday night. SJP, who was at the festival, told guests Adrien Brody and Kara Hui at a cocktail party at the Vitamin Water beach that “terror and excitement go hand in hand” when showing clips from a yet-to-be-finished movie. The final product opens Sept. 16.