When I mouse over the mining icon in the new wallet, it says "no suitable inputs were found." I've unlocked the wallet for mining...any idea what that message means or how to fix it?

Also, when I click on the "minting" tab and choose a date range, the number of expected coins goes down when I increase the number of days. (In other words, it predicts I'll earn more coins in 30 days than I'd earn in 60 days; more coins in 60 days than I'd earn in 90 days.) Any thoughts on that?