This episode's headline: Wall St. - Going Down; Newsmaker; Image Problems. ANCHOR: JAMES LEHRER; GUESTS: MARY FARRELL, Paine Webber; WALTER MONDALE, U.S. Ambassador, Japan; SEN. ROBERT BENNETT, [R] Utah; ANN LEWIS, Clinton-Gore Campaign; PAUL GIGOT, Wall Street Journal; ELIZABETH DREW, Author/Journalist; CORRESPONDENTS: CHARLAYNE HUNTER-GAULT; ELIZABETH FARNSWORTH;