Bonnie Erbe’s life took an ominous turn over Memorial Day weekend, but she doesn’t remember much of what happened. The longtime host of public TV’s To the Contrary was astride her Hanoverian horse, Stand Out, that Sunday, riding in a hunter/jumper show at the Prince George’s Equestrian Center in Upper Marlboro, Md. They approached a fence on the stadium course for a jump, but something went wrong. “The last thing I remember is hanging onto the horse’s neck and thinking, ‘Oh, no,’” Erbe said. Meanwhile in Baltimore, Cari Stein, former executive producer of the 20-year-old all-female news-analysis program, was entertaining a houseful of holiday guests, purposely ignoring her cellphone.