Index: branches/pap/ppStats/src/ppStatsReadout.c
===================================================================
--- branches/pap/ppStats/src/ppStatsReadout.c	(revision 23948)
+++ branches/pap/ppStats/src/ppStatsReadout.c	(revision 25027)
@@ -92,7 +92,7 @@
         }
         if (!psVectorStats(data->stats, sampleValues, NULL, sampleMask, 1)) {
-            psWarning("Unable to perform statistics on readout %s.\n", readoutName);
-            psErrorClear();
-        }
+	    psError(PS_ERR_UNKNOWN, false, "failure to measure stats for readout %s", readoutName);
+	}
+	// XXX raise if we get a NAN? psWarning("Unable to perform statistics on readout %s.\n", readoutName);
         psFree(sampleValues);
         psFree(sampleMask);