Director John Landis and two associates have been reprimanded by the Directors Guild of America for "unprofessional" conduct while filming "Twilight Zone: The Movie." Actor Vic Morrow and two children were killed July 23, 1982, when a powerful special-effects blast sent a helicopter crashing into the actors. The national board of directors of the guild, which voted to reprimand the three, also called the incident "prejudicial to the welfare" of the guild. The board's vote carries no disciplinary repercussions. Landis and four others were acquitted last May of all charges in connection with the accident. The director could not be reached for comment Tuesday.