STAGEHANDS power-drilled screws into sheets of plywood on the stage of the New York State Theater one morning late last month. Four layers — comprising 1,100 sheets — were laid down over the spongy floor that usually supports the delicate limbs of dancers. And workers installed an aluminum truss underneath so the floor would not bow or collapse under the extraordinary weight it would have to bear.

Meanwhile a giant chassis lay in a 53-foot trailer that was backed into a stage entrance. Metal skeletons, chunks of fiberglass and motors lurked in other trucks and throughout the theater’s bowels, all waiting to be assembled into an 18-ton rotating wall that will rest on top of the plywood armor.

The wall, 46 feet long and 28 feet tall at its highest, is the main scenic element of “Grendel: Transcendence of the Great Big Bad,” the much-anticipated new opera composed by Elliot Goldenthal and directed by his companion, Julie Taymor, which will open at the Lincoln Center Festival on Tuesday and be performed again on July 13, 15 and 16.

Rarely has one element of scenery loomed so large. Such concern is not just because the element itself is so enormous, or because “Grendel” is making its New York debut as the centerpiece of the festival’s 10th anniversary season, or even because the opera is its largest, and one of its most technically challenging, productions.

There is another reason for anxiety: Just before the work’s world premiere at the Los Angeles Opera, which co-commissioned the piece, the machinery of the wall failed, forcing the cancellation of the first performance, a highly unusual event. The mini-debacle, at the end of May, unleashed an unwanted wave of news media attention and chatter in the hothouse world of opera.

“Grendel,” based on the 1971 novel of the same name by John Gardner, retells the Anglo-Saxon poem “Beowulf” from the view of the monstrous Grendel. But for the creators and backers of the opera, it is the wall that has loomed as a monster.

Its technical problems have threatened to overshadow a prodigious creative achievement by a formidable artistic team, a work that has been more than 20 years in the making and has cost $2.8 million to produce.

“It screwed up one performance,” Ms. Taymor said. “It was a drag, and so much copy has been written about it. You say, ‘God sakes, it happens all the time.’ ” The show’s backers also like to point out that the delay was really just precautionary, that everything worked out in the end, and that audiences liked what they saw. “When they got it to work, it worked,” Ms. Taymor added, “and we’re very pleased.”

Still, Lincoln Center officials refused to let a reporter observe the wall’s installation, permitting only a brief glimpse of preparatory work from the auditorium. Access to backstage was denied, and a tape of the Los Angeles performance was allowed to be viewed only on an “off-the-record” basis. Officials and publicists offered a barrage of messages advising that the set was not the story.

Lincoln Center officials said they were confident that the wall would work faultlessly, as it did in subsequent Los Angeles performances. During assembly in the last week of June it tested fine, they said. But for some opera lovers, Lincoln Center devotees, Julie Taymor fans and informal odds-makers, in the days before the curtain rises the question inevitably would linger: Will the wall hold?

MS. TAYMOR said she and Mr. Goldenthal first began discussing an adaptation of “Grendel” as early as 1984, when they were working together on a musical theater piece. She had read the novel in college, at Oberlin, shortly after its publication and wrote a paper comparing it to the original poem. Mr. Goldenthal also was a fan of the novel.

“It was a big sensation back then,” she said. “It’s never really died with me or Elliot.” That summer, at a workshop in Milwaukee, they developed a brief sketch. In 1992 Mr. Goldenthal produced a scene. Encouragement from the music director Seiji Ozawa led him to envision “Grendel” as an opera.

“It just seemed right as an opera,” Mr. Goldenthal said. “In opera you look for collisions, dramatic collisions.”

“Grendel” offered the opportunity to dramatize the collision between modern themes, like the monster’s alienation, and the “mythic templates” of the poem’s medieval themes, he said.

“Both Elliot and I were attracted to that point of view, the outsider, the person who walks on the edge,” Ms. Taymor said.

The couple made proposals to a number of opera houses, including Los Angeles’s, to no avail. Ms. Taymor also spoke with Nigel Redden, who at the time was acting as a consultant for a proposed summer festival at Lincoln Center. But eventually she and Mr. Goldenthal moved on to other projects, a number of them collaborative.

In 2000 Plácido Domingo arrived at the Los Angeles Opera as its artistic director. (He is now general director.) He and Edgar Baitzel, the house’s chief of operations, began reviewing old proposals and came across “Grendel.” They reached out to Ms. Taymor, who was in town to work on her Broadway adaptation of the Disney movie “Lion King.” She put them in contact with Mr. Redden, who was by then the director of the Lincoln Center Festival, and the joint production was solidified in 2003.

Mr. Goldenthal stepped up work on the opera, his first, in earnest. Then came a serious setback. In December 2005, after falling asleep at a dining table in the couple’s airy Flatiron district loft, Mr. Goldenthal fell backward and struck his head, causing serious injury. The accident left him temporarily without speech and delayed progress on the opera by a month.

Normally laid back, with a hipster goatee and serious but not solemn manner, Mr. Goldenthal, 52, now speaks even more haltingly. “I realized it just affected my speech, but not my musical hard drive,” he said in a recent interview. Despite the injury he wrote the second act quickly. “I was thinking about the work so long, it was just standing in line to emerge.” Rehearsals began in early April for the Los Angeles production.

The designer was George Tsypin, a former architect. He built the set around a huge wall with 30 motors that rotates and moves up and down on the stage while an embedded platform revolves on a horizontal axis to form another plane for action.

Mr. Tsypin had executed elaborate designs before. For the Metropolitan Opera’s “War and Peace” he created a large domelike rotating platform, as well as a vast rotating set for Ms. Taymor’s “Magic Flute,” also at the Met.

The “Grendel” set was even more ambitious. With lighting designed by Donald Holder, one side of the wall portrays an icy, wintry landscape; the other, an earthy, muddy cave. It is called the “ice-earth” unit. About 80 percent of the action takes place on it.

At one point the wall was deemed too expensive, so it was reduced in size by 15 percent, Mr. Baitzel said. And though it was originally conceived to contain the chorus, it proved too narrow, and the singers had to be placed onstage, said Paul King, the Lincoln Center Festival’s production manager.

Meanwhile the wall was bedeviled by technical problems, which delayed rehearsals. As the dress rehearsal approached, Eric Owens — the bass-baritone who plays Grendel and appears onstage for almost the entire opera, including one scene where he flies through the air via a harness — recalls, “I just thought, ‘Oh my God, there were things we haven’t done.’ ”

And two days before the opera was to have had its premiere on May 27, the computer programs created to control the set failed, Mr. Baitzel said.

Officials of the opera sought to shield the cast from the problems. “They were trying to keep things positive for us,” Mr. Owen recalled. “Although I know behind the scenes they were pulling their hair out.” At the time, he recalled, stage crews were working 24 hours a day.

The house rigged up its own computer programs. But then new problems caused a motor to malfunction, immobilizing the inner platform.

The show’s technicians eventually managed to overcome those difficulties and find a way to make the electronics and the mechanics work together. By then, however, too much rehearsal time had been lost. It was decided the show could not go on.

The May 27 premiere was canceled. The performances of June 1 and June 3 were hastily repositioned as previews (a feature of Broadway but not the opera world). And the June 8 performance was declared to be the new official premiere.

Mr. Owens acknowledged that for him the delay came as a relief. “We desperately needed the extra time,” he said, and suggested it may also have helped generate some buzz for the show.

Mr. Goldenthal said he also was relieved, and recalled thinking, “O.K., it’s delayed four days, now I can define some orchestration, change the key of this.” As for Ms. Taymor, she used the time to adjust the staging in order to reduce the amount of action on the wall.

“The only thing I reflected on,” Mr. Goldenthal said, “was being thankful that people were not subjected to harm.”

The same could not be said of the show’s finances. The loss in ticket sales and the costs of extra rehearsal time came to nearly $400,000, according to Mr. Baitzel. “We went through hell here,” he said.

ON June 1 the curtain rose on the first public performance of “Grendel.” The wall functioned smoothly, as it did for the rest of the Los Angeles run.

“If it hadn’t failed” in rehearsal, Mr. Redden said, “you would have thought that this isn’t complicated at all. It was just silent and quiet and magical.”

The critics all took notice of the technical problems but were mixed in their reviews of the production.

In The San Francisco Chronicle, Joshua Kosman called it a “dazzling display of musical and theatrical inventiveness.” Timothy Mangan, writing in The Orange County Register, praised it as a “brilliant night of theater” with music “well up to the task of telling the story.”

Others were less kind.

“The opera accomplishes little through words or music,” wrote Mark Swed of The Los Angeles Times, though he noted, “There is quite a bit to look at.” He faulted the score as derivative and “mostly glue.” Critics for The Financial Times and Variety also disparaged the music.

But the Los Angeles Opera considered it a success and is looking to bring the opera back for five or six more performances in November 2007, Mr. Baitzel said.

The next chapter of “Grendel” began on June 19, when two trailer trucks set out on a cross-country trip to New York. Other trucks followed, one holding the chassis of the wall.

The wall had been designed to be easily adaptable to other theaters. But just to be sure, technicians from the Los Angeles Opera came along to help set it up. In the State Theater during the last week of June, an armature, or skeleton, was bolted or hinged together on top of the chassis and fiberglass panels were attached to make the exterior. A pivot was added for extra stability. And all the movements were tested along the way, Mr. King said.

According to Tony Cenicola, a photographer for The New York Times who was granted access to the hall, the stage was a harried scene during the week before the Fourth of July. Technicians struggled to get the set to respond to computer commands. Two technicians worked at two computers on rolling carts, and a third used a laptop. Others examined wires leading to the structure.

On June 28 the wall unit was again not functioning but appeared to be up and running by the evening, Mr. Cenicola said. On Friday, the last day of stage work before the Fourth of July, Lincoln Center officials said preparations were on track.

The two-act opera, of course, is far more than the set. Its cast includes 7 principals and 13 other roles, 58 choristers and 21 dancers, Ms. Taymor’s trademark puppets and masks, and an orchestra of 73. (The New York City Opera Orchestra will be in the pit, with Steven Sloane conducting.)

Eric Owens has a marathon part in the role of Grendel, the spawn of Cain who grows sick on the “sour meat” of men, a monster “huge as horror” and “hard as bone.” He is portrayed as a child picked on by humans, a lonely beast nursing resentment, an outsider watching men waging war and desecrating the landscape, a violent being searching for meaning.

“Both subhuman and superhuman, bestial and divine, Grendel mirrors modern man,” Ms. Taymor has written, “completely self-conscious, trapped in his own history, seeking the possibilities of optimism and redemption.”

But it all comes back to the wall, which Ms. Taymor describes as the symbol of the whole opera. Grendel, “has to be on another level,” she said. “He has to be isolated from human beings in order to observe them.” And the wall is the symbol of that isolation.

Mr. Tsypin has written that the role of an opera set designer is equal to those of the composer, conductor and director. “In opera the spectacle is important,” he said in an interview. “The visuals connect so directly with the music, and the plot, the narrative, the libretto sometimes take a secondary role.”

He described the wall as the opera’s “backbone,” both as an image and an organizing device.

“It’s almost like a cosmic clock,” he said. “It revolves the seasons, spring turns into summer, the ice turns into earth. There’s also a kind of very abstract starry sky in the background.

“The whole thing feels like some cosmic object in space,” he continued. “It captures the existential nature of the piece and the soul of Grendel, and the loneliness of Grendel in the universe.”

Until the curtain rises at Lincoln Center, the wall seems to have captured the soul of the production as well.