The state of California has ordered that 15,000 brand new touch-screen voting machines not be used in next week's presidential election.
These electronic machines were manufactured by Diebold Inc., a North Canton, Ohio-based company that also specializes in automated teller machines and electronic security.
California election officials say there are serious flaws with the machines and that Diebold repeatedly misled the state about them.
"[Diebold] literally engaged in absolutely deplorable behavior and, to that extent, put the election at risk, jeopardizing the outcome of the election," said California Secretary of State Kevin Shelley.
Some 50 million Americans -- about 29 percent of voters in the United States -- are expected to use touch-screen electronic voting machines in next week's election.
The problem came to light in the California primary last March when a massive failure of the electronic voting machines left thousands of San Diego residents unable to cast their votes.
Diebold's director of marketing, Mark Rapke, said it was a regrettable error the company has fixed.
"Of course we would have wished the situation would not have happened, but it did," Rapke told ABC News. "There was back up available. But again, with additional familiarity with the system, again, this problem would not have happened."
But a former Diebold technical worker, James Dunn, told ABC News the company was aware of the software and electronic problems before the election, and never reported them.
"The machine would lock up or lose its software load. A very uncommon thing and not a good thing," said Dunn. "And once that machine's locked up you're unable to produce voter cards, which means you're unable to open the election voting machine and people can't vote. But they shipped it anyway."
Experts have raised questions about the machines' security features, which some say can be easily defeated, making it possible to manipulate the actual vote count.
"In all of my consulting work and all of my work in industry I've never seen a system that I thought was this vulnerable to abuse," said Avi Rubin, a professor of computer science at Johns Hopkins University in Maryland, who, along with other security experts, analyzed Diebold's source code for the electronic voting machines.
He said tampering of the machines would be easy. "It would only take a few minutes to erase a vote," he said.
Diebold also has been fighting a perception problem. Its chairman, Walden O'Dell, is a major contributor to the Republican Party. O'Dell is a "pioneer," which means he's raised at least $100,000 for the president's re-election campaign.
In a letter dated Aug. 14, 2003, O'Dell said he was "committed to helping Ohio deliver its electoral votes to President Bush." This pledge raised concerns among Democrats, including California Secretary of State Shelley.
"I think it calls into question the integrity of the process," Shelley told ABC News.
A Diebold spokesman said O'Dell's letter was a mistake and had absolutely nothing to do with the integrity of its machines. The spokesman said the company no longer permits its executives to be involved in politics.
ABC News' David Scott and Marni Lane contributed to this report.