Index: trunk/ppStack/src/ppStackLoop.c
===================================================================
--- trunk/ppStack/src/ppStackLoop.c	(revision 17429)
+++ trunk/ppStack/src/ppStackLoop.c	(revision 17625)
@@ -478,13 +478,19 @@
                                              subKernels->data[i]); // Pixels to reject
             psFree(inspect);
-            float frac = reject->n / (float)(outRO->image->numCols * outRO->image->numRows); // Pixel fraction
-            psTrace("ppStack", 5, "%ld pixels rejected from image %d (%.1f%%)", reject->n, i, frac * 100.0);
-            if (frac > imageRej) {
-                psWarning("Image %d rejected completely because rejection fraction (%.3f) "
-                          "exceeds limit (%.3f)", i, frac, imageRej);
-                psFree(reject);
-                // reject == NULL means reject image completely
-                reject = NULL;
+            if (!reject) {
+                psWarning("Rejection on image %d didn't work --- reject entire image.", i);
                 numRejected++;
+            } else {
+                float frac = reject->n / (float)(outRO->image->numCols * outRO->image->numRows); // Pixel frac
+                psTrace("ppStack", 5, "%ld pixels rejected from image %d (%.1f%%)",
+                        reject->n, i, frac * 100.0);
+                if (frac > imageRej) {
+                    psWarning("Image %d rejected completely because rejection fraction (%.3f) "
+                              "exceeds limit (%.3f)", i, frac, imageRej);
+                    psFree(reject);
+                    // reject == NULL means reject image completely
+                    reject = NULL;
+                    numRejected++;
+                }
             }
             rejected->data[i] = reject;