Index: trunk/psModules/src/imcombine/pmSubtractionMatch.c
===================================================================
--- trunk/psModules/src/imcombine/pmSubtractionMatch.c	(revision 25425)
+++ trunk/psModules/src/imcombine/pmSubtractionMatch.c	(revision 25464)
@@ -628,5 +628,9 @@
     variance = NULL;
 
-    if (!pmSubtractionBorder(conv1->image, conv1->variance, conv1->mask, size, maskBad)) {
+    if (conv1 && !pmSubtractionBorder(conv1->image, conv1->variance, conv1->mask, size, maskBad)) {
+        psError(PS_ERR_UNKNOWN, false, "Unable to set border of convolved image.");
+        goto MATCH_ERROR;
+    }
+    if (conv2 && !pmSubtractionBorder(conv2->image, conv2->variance, conv2->mask, size, maskBad)) {
         psError(PS_ERR_UNKNOWN, false, "Unable to set border of convolved image.");
         goto MATCH_ERROR;