Index: trunk/psModules/src/imcombine/pmSubtractionStamps.c
===================================================================
--- trunk/psModules/src/imcombine/pmSubtractionStamps.c	(revision 31451)
+++ trunk/psModules/src/imcombine/pmSubtractionStamps.c	(revision 31537)
@@ -834,15 +834,21 @@
             }
 
-            psStatsInit (stats);
-            if (!psVectorStats (stats, flux1, NULL, NULL, 0)) {
-                psAbort ("failed to generate stats");
-            }
-            float f1 = stats->sampleMedian;
-
-            psStatsInit (stats);
-            if (!psVectorStats (stats, flux2, NULL, NULL, 0)) {
-                psAbort ("failed to generate stats");
-            }
-            float f2 = stats->sampleMedian;
+            float f1 = NAN;
+            if (flux1->n > 0) {
+                psStatsInit (stats);
+                if (!psVectorStats (stats, flux1, NULL, NULL, 0)) {
+                    psAbort ("failed to generate stats");
+                }
+                f1 = stats->sampleMedian;
+            }
+
+            float f2 = NAN;
+            if (flux2->n > 0) {
+                psStatsInit (stats);
+                if (!psVectorStats (stats, flux2, NULL, NULL, 0)) {
+                    psAbort ("failed to generate stats");
+                }
+                f2 = stats->sampleMedian;
+            }
 
             stamps->window1->kernel[y][x] = f1;