The difficulties in reporting last night on nip-and-tuck races across the country was exacerbated by a computer failure of a key system used by television networks to explain the results.

Officials at the service that provides national and state voting results for the country's TV networks and other major media outlets said it wouldn't release detailed exit-poll results last night, saying they lacked confidence in their own computer analysis of that data.

The Voter News Service was created under a partnership of the Associated Press and the five major networks - ABC, CBS, CNN, Fox News Channel and NBC - to generate comprehensive election returns. Officials said a software problem led them to doubt the fidelity of the compiled voting results fed by an army of more than 30,000 people hired for the task.

Taken with a surprisingly high number of tight races in states throughout the country for House, Senate and governor, editors and news executives were predicting a long, long night for those producing coverage of the elections. "This is really a spectacular crackup," said Ronald Brownstein, national political correspondent for the Los Angeles Times, which did not subscribe this year to the service.

"It's like a perfect storm," said Linda Mason, CBS' vice president for public affairs, who sits on the board of directors of the Voter News Service.

She oversaw her network's investigations into the five-star media fiasco of 2000, when unreliable exit-polling data led all the networks to project a win prematurely in Florida by Democratic presidential nominee Al Gore, seemingly putting him over the top in his bid for the White House.

The networks then withdrew that call and later awarded it to Republican George W. Bush, a prediction then taken back as the final outcome dragged through the courts for weeks.

Yesterday's snafu made for a night more attuned to 1980s technology than to the sensibility of instant media gratification prevalent in 2002. Some VNS staffers were toting up numbers and calculating figures by hand, instead of using the faulty computer systems at the service's Brooklyn, N.Y., headquarters.

For the past two years, VNS has moved to overhaul the "exit poll" system entirely, both on the state and national level. The polling is intended to deliver to its members a demographic breakdown of votes for candidates, as well as some context for why people voted the way they did. Such material is standard fodder for political analysts, particularly those on the cable news stations, which carried hours of continuous coverage.

But those details would not be available last night to news organizations, or curious citizens, and it remained unclear whether the data would be available later on.

"It's staggering to think about," said Brownstein. "We have this incredible data set that can track changes in the electorate. Can you imagine if we won't get it for 2002? I rely on it enormously for my reporting - not just for tomorrow but the next two years."

The foul-up did not affect the news service's largely separate system to project winners for its members, long a basis of competition among broadcasters. The VNS receives results from staffers who are scattered at precincts throughout the country to collect running tallies of votes as they're offered.

Nonetheless, all news officials interviewed at various outlets said they would be very conservative about "calling" races.

Far in advance, networks said they would make no projections for a race until all the polls in that state or district were closed. And anchors and commentators on the air also warned viewers of the VNS exit poll's failure. Fox News Channel's Tony Snow, for example, issued a "note of caution," telling viewers "there's a lot of controversy" over the VNS data.

Many cable outlets relied on recent polling data - including surveys conducted yesterday - to offer a seeming replica of the kind of information viewers have become accustomed to seeing on election night.

Television news executives said they had foreseen difficulties in recent weeks, as VNS tested its computer operations.

CBS hired an extra 10 reporters in 10 states with tight races, including Maryland. CNN created its own system shadowing VNS, calling it "Real Vote," that relies upon more than 600 people in key areas. National Public Radio relied on other networks, crediting them with their projections, as well as unofficial vote tallies.

And almost all major news agencies are members of the Associated Press, which compiles its own totals of votes in every precinct, district, county and state in the country.

During much of the evening, CNN.com would report partial results from the Maryland governor's race more quickly than AP was able to move its tallies.

"When they get really, really close, you couldn't call it even under the old system," Mason said. "These are the closest elections we've had in memory."