Producers of “Spider-Man Turn Off the Dark” have been forced to delay by three weeks the official opening of the costly and complicated show, and it will only open its doors for previews after the busy Thanksgiving holiday.

“Shows like ours, that embrace the challenge of opening on Broadway without an out-of-town tryout, often need to adjust their schedules along the way,” lead producer Michael Cohl said in a statement released Friday, citing an “unprecedented level of technical artistry.”

Originally scheduled to begin previews on Nov. 14 with an opening four days before Christmas, the show will now begin previews on Nov. 28 and finally open on Jan. 11, a less-than-ideal timetable for luring the crowds that descend on Broadway over the holidays.

“That’s usually a sign that there’s trouble in River City,” says Robert Westenberg, a Tony Award-nominated actor whose Broadway credits include “Les Miserables,” “Zorba” and the original 1987 run of “Into the Woods,” which he recalls was delayed for several weeks while Stephen Sondheim tinkered with the musical before it finally opened. When it did, it ran for two years.

Westenberg, who now teaches theater at Drury University in Springfield, Mo., says many reasons can delay a show’s opening, including weak stories or songs, unfinished costumes, not-ready-for-prime-time production values and unready stars.

“They have to do this cost-benefit analysis in terms of how many weeks is it going to take to hammer it into the kind of shape where it’s going to be critic-proof, and how many weeks can they afford to do that without anybody coming in to put money in the coffers,” he says. “It’s a tough call.”

The reported $60 million musical is, by any measure, a huge undertaking. It will have a 41-member cast, 18 orchestra members and aerial stunts designed by a longtime Cirque du Soleil alum that will shoot actors up to 40 mph through the air and over the audience. Its promotional material promises “a thrilling experience in ways never-before-dreamed-possible in live theater.”

The delay is just the latest blow for a musical that has been in the works for more than six years. Producers have come and gone, and so have cast members: Evan Rachel Wood and Alan Cumming were once cast as Mary-Jane and the Green Goblin. At one point, the musical was supposed to open in February 2010.

Besides timing troubles, two on-set accidents have injured actors, including one who had both his wrists broken when he practiced an aerial stunt. And inspectors from the New York State Department of Labor, which must approve all stunts that go over an audience, were unable to complete a recent safety review; producers said they were unprepared to show all the stunts in one day.

“I’m not surprised that ‘Spider-Man’ is delayed,” said a longtime theater producer not connected to the comic book musical, who asked that his name not be used so he would not damage his relations in the Broadway community. “They are building a musical that costs three times as much as the biggest musical we’ve seen previously.”

Until now, “Shrek the Musical,” which opened in 2008, is believed to be Broadway’s costliest show with a price tag reported to have been $25 million and it failed to make its investors money. By comparison, “The Phantom of the Opera” cost about $12 million in 1988 – around $22 million in today’s dollars – and “Wicked” cost $14 million to mount in 2003 and both are still chugging along on Broadway and are two of the most successful shows ever.

The Spider-Man musical will star relative unknowns – Reeve Carney as Peter Parker, Jennifer Damiano as Mary Jane Watson and Patrick Page as the Green Goblin – in the story by Glen Berger and Julie Taymor, who is also directing. The music is by U2’s Bono and The Edge, and features moody guitar-heavy arena rock, including the song “Boy Falls From the Sky,” which U2 has been playing on tour.

During a set visit in early October, Taymor, who won a Tony Award for directing “The Lion King,” was firmly in charge and the technical run-through seemed relaxed. Cohl said things were on track, both financially and in terms of schedule. He would not comment to The Associated Press on Friday.

Other shows this month have had complications. The opening of a musical based on Pedro Almodovar’s “Women on the Verge of a Nervous Breakdown,” which, like “Spider-Man” originated on Broadway without benefit of a practice run elsewhere, was also delayed and opened to mostly negative reviews, citing an unfocused production. And the upcoming Broadway opening of “The Merchant of Venice” has been delayed after actress Lily Rabe pulled out for several preview performances citing family reasons.

But “Spider-Man Turn Off the Dark” has drawn the most attention because of its sheer size and audacity. The producer not connected with the show says he still has hope.

“I wouldn’t count them out just yet,” he said. “We’re about to see something exciting. Whether it can pay for itself is a whole other issue.”

Click here for the Spider-Man On Broadway website.