The problem, which appears to have affected only a small number of customers, was reported on the discussion forum of Apple's support site this week. The dead spots were in a variety of locations and occurred irrespective of the software being used.

Many of the customers reported bringing the phone back to an Apple store, where in many cases they received a loaner phone at no charge while the broken handset was being repaired. Apple, according to the reports, was not handing out new phones as replacements.

A minority of customers, however, reported less than satisfactory service at the stores. "I went to the iPhone bar a couple weeks ago, and the guy told me this was just how the screen is, and that it was the length of my nails!!" a Chicago resident who used the name Newtype said.

Another customer reported taking his broken iPhone to an Apple store in Westchester County, N.Y., where a manager denied such a problem existed and refused to waive the $29 fee for a loaner phone. "He denied that he had the discretion to replace the phone or waive the loaner fee. Great product, support not so great," the person who went by the name Tjrubeo said.

Apple was not immediately available for comment on Friday.

The iPhone's unique touch-screen interface is among the innovative features that Apple has used in justifying the high cost of the iPhone, which is as much as $600. Other vendors sell less-expensive smartphones that are also capable of surfing the Web and contain similar software.

An advantage of the iPhone, however, is it sleek design and large screen that displays Web pages pretty much as they appear on a PC. According to recently published patent applications, Apple is working on an interface for "computing devices" that would respond to voice commands.

The initial success of the iPhone, which hit the market June 29, has attracted the attention of lawyers. IPhone-related lawsuits have included one for alleged patent infringement, and another over Apple's decision not to include a user-replaceable battery in the device. Buyers have to ship the phone to Apple to have the battery replaced.