This episode's headline: Argentina and the IMF. The guests include WILLIAM CLINE, Institute for International Economics; RIORDAN ROETT, Johns Hopkins School of Advanced International Studies. Byline: In New York: ROBERT MacNEIL, Executive Editor; In Washington: JIM LEHRER, Associate Editor; DAN WERNER, Producer; PATRICIA ELLIS, Reporter; Videotape segment: JOHN ARDEN, Reporter/Producer; JORGE CASAL, Camera; RAUL BOADA, Sound