Standard & Poor's/Case-Shiller's vs. National Association of Realtors

In the recent days two home sales reports were published that in my opinion totally contradict each other. The first report comes from the Standard & Poor's/Case-Shiller's U.S. National Home Price Index which in the second quarter of 2009 recorded the first rise in home values since 2006. The other report is from the National Association of Realtors (NAR) that reported that one-third of all home sales over the past few months were either a foreclosure or a short sale. How can you reconcile those two reports? A third of all homes sold on a fire sale maks the property values climbing?