Pentagon officials arenít happy about a report they have to deliver to Congress on March 30 about the military threat Cuba poses to the U.S. The report, ordered by Florida Senator Bob Graham, must detail whether Havana could attack American territory with chemical and biological weapons. Why the worry? Cuba has no such weapons, and the Pentagon has withdrawn forces from southern Florida because it no longer considers the island a military threat. But the report will have to concede that Fidel Castro does have a large pharmaceutical industry that could produce biological agents. He also possesses six Russian MiG-29 jets -- delivered by Moscow during the Cold War -- that are equipped to carry such theoretical weaponry. Senior Pentagon officers, who hope Pope John Paul IIís visit to Cuba this week will help ease tensions, privately favor normalizing relations with Havana. They fear that the report will only throw red meat to congressional and Cuban-American hard-liners, who will demand that sanctions be tightened and U.S forces be returned to Florida.