S&amp;P 500 DOWN 48.18 POINTS, OR 1.27 PERCENT, AT 3,753.60 AFTER MARKET OPEN  DOW JONES FALLS MORE THAN 460 POINTS, NOW DOWN 1.5%  NASDAQ  DOWN 86.13 POINTS, OR 0.77 PERCENT, AT 11,161.46 AFTER MARKET OPEN