(WGN-AM)-A computer central to the new touring production of Disney's "Mary Poppins" malfunctioned about 15 minutes into Saturday night's Chicago performance at the Cadillac Palace Theatre, causing the entire show to be shut down and the frustrated audience sent home.

According to several people who were there and sent descriptive (and angry) e-mails to the Tribune, the problem occurred shortly after the start of the technically complicated production, which has two weeks left in a Chicago run of several months. Audience members were asked to cool their heels for about 45 minutes before it was announced from the stage that, for safety reasons, the show could not go on.

There have been anecdotal reports throughout the run that a pesky, new computer system was causing problems with the show. Indeed, on the opening night in Chicago, a few technical cues malfunctioned. But there has been nothing on this scale to date.

Eileen LaCario, a vice president at "Poppins" presenter Broadway in Chicago, confirmed these events and said Sunday morning that such a mid-show cancellation is "very unusual."

"This particular malfunction made it impossible to produce a safe performance," she said.

"Mary Poppins" is one of the most technically demanding touring musicals, not least because the title character flies all the way to the back of the theater.

LaCario also said that those who bought tickets for the canceled show would be offered their choice of refunds or tickets to an alternate performance during the next two weeks. The best availability, LaCario said, is over the July 4 weekend.

Issues with the non-reimbursement of parking and ticketing fees (typical when live events are canceled) should be addressed at the Broadway in Chicago customer-service line at 312-977-1711. Exchanges can also be made through Ticketmaster by calling 800-653-8000.

(The Chicago Tribune contributed to this story)

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