There were collective groans on Broadway Wednesday, after New York’s Daily News reported that “The Producers” costar Matthew Broderick will have to leave the smash show for six weeks in the fall, so he can film an ABC-TV version of “The Music Man.” “The dates are not set in stone yet,” a rep for the actor, 41, told the paper. “The important thing is that he’s definitely coming back to ‘The Producers.’ ” In it, Broderick, who costars with Nathan Lane, plays timid accountant Leo Bloom, who sees his dream of becoming a big Broadway producer come true — only to dissolve into a hilarious nightmare.