THE German government denied a report on Tuesday that Libyan leader Muammar Gaddafi had admitted to a German official that Tripoli was involved in the Lockerbie bombing and an attack on American soldiers at a Berlin nightclub in 1986. The Foreign Ministry, however, declined either to confirm or deny the report in the respected Frankfurter Allgemeine daily that Berlin’s ambassador to Washington had written in a secret diplomatic telegram that Gaddafi had made such an admission in March to a senior aide to Chancellor Gerhard Schroeder. And while Schroeder’s spokesman denied, in guarded terms, that the Libyan leader had made any confession, the report did force him to confirm that the chancellor’s foreign affairs adviser, Michael Steiner, had indeed held secret talks with Gaddafi on March 17.