Not since Nero fiddled while Rome burned has there been a musical event as catastrophic as what happened last night in the Kennedy Center Concert Hall:

* There was no music at all for the first half-hour; the guest artist arrived late (he thought the concert was in Baltimore).

* The music for the first selection was lost and it never did get performed.

* The conductor's music stand collapsed midway through Haydn's lovely Andante cantabile, shortly before an electrical problem plunged the room into darkness.

* The bassoon kept coming apart during the final concerto, and the vocal soloist (a large dog that looked something like a St. Bernard) fell asleep during the cantata.

* A woodwind trio came on and tried to play a sonata, but it was interrupted by a hostile brass ensemble in the top tier at the back of the hall.

The only thing worse than the accidents that interrupted the music was the music itself. Except for the ill-fated Haydn, the concert was devoted entirely to works of P.D.Q. Bach, a composer of dazzling obscurity. As the world's leading authority on the subject summed it up: "The only times in his life P.D.Q. Bach wasn't being ignored was when he was being avoided."

The guest artist was, of course, Peter Schickele, professor of musical pathology at the University of Southern North Dakota at Hoople. Schickele has discovered (some say he has forged) all the known works of P.D.Q. -- the legendary youngest and least eminent son of Johann Sebastian -- who has been called "the most justly neglected composer of the 18th century."

Schickele introduced each of the selections on the program, played the bassoon in the Concerto for Bassoon vs. Orchestra, put on a dog suit to solo in the cantata "Wachet Arf!" (S. K9) (probably collecting an extra fee for that) and conducted several works after making some possibly libelous remarks about Andrew Litton, who also conducted the National Symphony.

He also insulted the audience -- but, of course, that was expected. While huckstering his latest P.D.Q. Bach album, "A Little Nightmare Music," he noticed that the spotlights reflected off its shrink wrap like a mirror and began flashing the light in the audience's eyes. "It isn't often you get a light show with classical music," he said. "There's a cassette, too; it works just as well, but you don't get as big a flash." The record is available from Vanguard, which Schickele described as "a good label -- better than my first label, which was Fruit of the Loom."

He also plugged "The Definitive Biography of P.D.Q. Bach," of which he is the author. "Is there anyone here who owns the 'Definitive Biography?' " he asked. A substantial part of the audience applauded, and Schickele's remark, "P.T. Barnum was right," was picked up by the microphone.

Schickele brought some North Dakota weather with him last night and, although the concert was sold out, there were empty seats for the people who bought standing-room tickets at the last minute. Still, the Concert Hall was nearly filled -- a remarkable situation considering the weather and even more remarkable considering the program. There will be a repeat performance tonight. (Refunds will not be given for returned tickets.)

Those who go tonight expecting to hear the "Desecration of the House" Overture may as well forget about it. After the rehearsal (there was a rehearsal?), the orchestral parts "were sucked up by an air conditioning duct and are now circulating somewhere in the building," he said. "I guess that's one piece you get out of." During the Andante cantabile, some papers blew out onto the stage from what may have been an air conditioning vent, but there were not enough to supply the whole orchestra with a whole overture. Sometimes the fates are kind.

The "Hindenberg" Concerto (S. LZ-129) will undoubtedly be performed again, for better or for worse. It is mostly a plagiarism of ill-matched snippets from papa Johann Sebastian's "Brandenburg" Concertos, but it also steals some harmonies from Tchaikovsky and some cadences from Ravel's "Bolero."

When Schickele came out to conduct it, he reached out, as is customary, to shake the hand of concertmistress Elizabeth Adkins, who crossed her arms and glared at him. A possible reason could be heard later in the cadenza she had to play for violin with cymbals as accompaniment -- or, more precisely, interruption.

Other features were the balloons that popped up mysteriously from midorchestra during the slow movement and the eloquent solo of percussionist F. Anthony Ames on sandpaper blocks -- an instrument rarely given solos in the 18th century.

The best thing that can be said about the "Echo" Sonata is that it did not last very long. In the concluding Bassoon Concerto, soloist Schickele kept taking his instrument apart but unfortunately managed to produce notes anyway.