Three Senate Democrats proposed emergency legislation today to reimburse states for printing paper ballots that can be ready at polling places in case of problems with electronic voting machines on Nov. 7. The proposal is a response to grass-roots pressure and growing concern by local and state officials about touch-screen machines. If someone asks for a paper ballot they ought to be able to have it," said Senator Barbara Boxer of California. Dozens of states are using optical-scan and touch-screen machines to comply with federal laws intended to phase out lever and punch-card machines after the hanging-chads confusion of the 2000 presidential election. Widespread problems were reported with the new technology and among poll workers using the machines this year in primaries in Arkansas, Illinois, Maryland, Ohio and elsewhere. Local and state officials have expressed concern that the new systems might not be ready to handle increased turnouts. Election experts fear that the lack of a paper trail with most touch-screen machines will leave no way to verify votes in case of fraud or computer failure. Last week, Gov. Robert L. Ehrlich Jr. of Maryland, a Republican, joined the skeptics, saying he lacked confidence in his state's new $106 million electronic system and suggesting that state officials offer all voters paper ballots as an alternative.