It was hot and almost airlessly humid on May 9 in San Juan, Puerto Rico. Most of the businessmen along the city's "Golden Mile"-a grim strip of banking and finance office towers-had their shirtsleeves rolled up and their collars undone. Norman Kleinberg, however, kept his jacket on; he didn't know when he might have to step back into court. Kleinberg. 43, a partner at New York's Hughe's Hubbard & Reed, was one of about 30 lawyers standing around in the mezzanine lobby of San Juan's Citicorp Tower. inside was the makeshift federal courtroom that since early March has been the main site of the massive case stemming from the 1986 fire that killed 97 people at the San Juan Dupont Plaza Hotel.