The nation has spent too little time on community problems that have arisen from the country’s housing crisis, the CEO of the Boston Federal Reserve said at a national summit about REO and vacant property issues. “Rather than treating the symptom — the high REO problem — we need to better understand how to resolve the more general problems in communities that lead to higher concentrations of REOs and exacerbate the effects of high REOs,” said Eric Rosengren, president and CEO of the Federal Reserve Bank of Boston.