Frozen screens (search) and malfunctioning computers plagued some Super Tuesday (search) voters who tried to cast electronic ballots, and experts predict such problems will be repeated on a national scale in November.

In California's San Diego County, touchscreens failed to boot properly, causing delays of up to two hours and forcing some voters to other polling places - where they cast old-fashioned paper ballots.

Other counties in California, Georgia and Maryland reported problems with encoders, the devices that allow touch-screen computers to display candidate and ballot measures specific to one county.

Elections officials blamed improperly trained poll workers, especially in counties that recently switched from antiquated punch-card and lever systems to touch-screen terminals.

"There have been a few human errors, which you have in any election," said Linda Lamone, Maryland election laws administrator.

Kimball Brace, president of Washington-based political consulting firm Election Data Services (search), said it's unrealistic to expect thousands of poll workers nationwide to get up to speed on complicated equipment immediately.

"Eventually, things will go smoother, but the first couple times will have bugs, no matter what system you switch to," Brace said.

Dozens of states are installing touch-screen terminals (search) for the November general election. The federal government provides matching funds to counties that modernize voting equipment, in hopes of eliminating hanging chads, confusing butterfly ballots and other problems that plagued Florida in 2000.

In November, at least 50 million people will vote on touch-screens, compared with 55 million using paper, punch cards or lever machines, according to Election Data Services.

Some computer scientists say electronic systems expose elections to hackers, software bugs and power outages - with potentially catastrophic consequences. Critics say that because most electronic voting terminals do not produce paper records, there's no way to ensure accurate recounts.

New Jersey Democratic Rep. Rush Holt (search), author of a bill to require paper records for every electronic ballot, said that although the Super Tuesday mishaps were not catastrophic, they foreshadow trouble in November.

"Unless Congress deals with this problem immediately by requiring voting machines to produce a paper record voters can verify we're going to have more of these occurrences each time we have an election, including this November," Holt said Tuesday. "The only question is, how long it will take before voters lose faith in a system that they thought was being fixed?"