SAN FRANCISCO -- California's ambitious solar-energy rebate program is slumping in the state's deep, prolonged housing crisis. Builders of new homes filed 139 rebate applications in January and 159 in February, according to California Energy Commission data. That is down from 709 in December and 485 in November last year. The solar program's slide reflects the mood in the economy and the downturn in the housing market, in which new-home construction fell to a record low last year as banks stopped lending and foreclosures spread. An energy commission official drew a direct link between stalled solar activity and the housing freeze.