This episode's headline: Nuclear Challenge; In the Pipeline; Internet Piracy; Crackdown in Cuba. ANCHOR: JIM LEHRER; GUESTS: J. ROBINSON WEST; FALAH ALJIBURY; CHRISTOPHER FLAVIN; AMY JAFFEE;JOSE MIGUEL VIVANCO; FRANK CALZON; CORRESPONDENTS: KWAME HOLMAN; RAY SUAREZ; SPENCER MICHELS; MARGARET WARNER; GWEN IFILL; TERENCE SMITH; KWAME HOLMAN