Record labels and music publishers won a round in their copyright lawsuit against Napster and its two lead investors when a judge ruled that Hummer Winblad Venture Partners improperly urged its employees to delete e-mail about the pioneering song-swapping service. If the 3-year-old San Francisco lawsuit reaches trial, jurors will be told they can infer that the e-mail would have hurt the venture capital firm's defense, U.S. District Judge Marilyn Hall Patel ruled.