A new federal program is offering aid with a sweet kicker: It doesn't need to be repaid. For the roughly four million homeowners who have fallen behind on their mortgage payments, the federal government is offering yet another remedy: free money to catch up on their loans. The effort, called the Emergency Homeowners Loan Program, is the latest in the federal government's efforts to slow down the flood of foreclosures a necessary step to a meaningful recovery in the housing market, says a Department of Housing and Urban Development official. For people who have lost their jobs, the $1 billion program offers loans of up to $50,000 that don't actually need to be repaid, if applicants meet certain requirements.   The goal, says HUD, is to offer short-term aid to people who look like they'll be back on their feet soon. But critics say the loans may leave homeowners worse off in the long run. "This is a short run