Updated from June 23 with analysts' comments.

The latest problem for

Boeing

(BA) - Get Report

involves about three dozen stress points, each one to two square inches, where the 787 Dreamliner's wings are joined to the aircraft's body, and the amount of stress at the joint is higher than anticipated.

On the one hand, with airplanes, it is good to catch problems early. On the other hand, the first test flight for the long-awaited 787aircraft will be delayed indefinitely. The first 787 delivery was once scheduled for May 2008.

One other notable event in the time period: Less than two weeks ago, at the Paris Air Show, Boeing reaffirmed that the first test flight would take place this month.

Investors don't like repeated delays in product introductions, no matter how desirable the product is. "This enormously complex program continues to throw a new curve ball every six months, technically and financially," wrote analyst Peter Arment of Broadpoint AmTech, in a report Wednesday.

The Boeing 787 Dreamliner

Analyst Mike Derchin of FTN Equity Capital wrote Wednesday that deliveries have been delayed four times and said, "The delays have been costly in terms of billions of dollars in added expenses, penalties and credibility."

Also Wednesday, analyst Rob Stallard of Macquarie Research wrote that he still rates Boeing outperform but concedes expectations for the 787 program, limited as they were, are not being met. "We thought first flight by the end of June should have been a low-risk proposition given comments by management last week at the Paris Air Show," he says. "We had been more concerned about the ability of Boeing to make first delivery on time as well as how fast it could ramp production."

Stallard continues to anticipate 20 deliveries in 2010, 40 in 2011 and 60 in 2012, but notes "investors should build in conservative expectations about the 787's progress."

At midday Wednesday, shares in Boeing, a

Dow Jones Industrial Average

component, were trading down 2% to $42.98, after losing 6.5% on Tuesday. The shares began trading this year at $42.80 and have essentially returned to their Jan. 2 level, just as the

S&P 500

has. After hitting a 52-week-low around $29 on March 3, Boeing shares traded as high as the $53 range early this month.

The latest problem was discovered late last month, while engineers were "bending the wings of the full-scale test airplane," said Pat Shanahan, general manager of airplane programs, on a conference call Tuesday with reporters and analysts. But it was not until Friday that the company decided it would be largely pointless to go ahead with the first flight without first fixing the problem. Boeing said it will announce a new first flight and first delivery schedule in several weeks and will update financial guidance in July.

The problem exists in about 18 places on each side of the aircraft, and involves "a couple of square inches of stress concentration (located) along the joint between the wing and the side of body," said Scott Fancher, general manager of the 787 program. "We saw strain gauges on the aircraft not meet our predictions (and) we saw a number of things indicative of what the strain gauges were saying."

To fix it, "a handful of parts that you could literally hold in your hand (will) be added to the structure," he said. The cost and weight of the repair will be negligible, he said. The wing was made by

Mitsubishi

, the side-of-body joint by

Fuji

, and the design by Boeing: all three companies will work to develop a solution.

Customers were told of the new delay starting Monday night, said Scott Carson, CEO of Boeing Commercial Airplanes. "All of them respected the process with which we are working and respected our judgment," he said. "Obviously, they will be monitoring our process."