Warner Bros. TV has signed an exclusive three-year production and development deal worth an estimated $2 million to $3 million with Paul Manning, supervising producer on NBC’s hit drama “ER.”Manning will develop, create and produce all forms of programming, and he’ll remain as a consultant on “ER” next season. He first started working on “ER” as a co-producer in its first season. He was later promoted to supervising producer, and he has written 14 episodes. Manning started his career on the drama “L.A. Law,” writing or co-writing 20 episodes. The deal was announced by Tony Jonas, president of Warner Bros. TV, and it was brokered by Rob Carlson at the William Morris Agency and Cliff Gilbert-Lurie and Skip Brittenham of Ziffren, Brittenham, Branca and Fischer.