Index: trunk/psModules/src/imcombine/pmSubtractionMatch.c
===================================================================
--- trunk/psModules/src/imcombine/pmSubtractionMatch.c	(revision 20465)
+++ trunk/psModules/src/imcombine/pmSubtractionMatch.c	(revision 20505)
@@ -98,6 +98,6 @@
                         int inner, int ringsOrder, int binning, float penalty,
                         bool optimum, const psVector *optFWHMs, int optOrder, float optThreshold,
-                        int iter, float rej, psMaskType maskVal, psMaskType maskBad, psMaskType maskPoor,
-                        float poorFrac, float badFrac, pmSubtractionMode subMode)
+                        int iter, float rej, float sysError, psMaskType maskVal, psMaskType maskBad,
+                        psMaskType maskPoor, float poorFrac, float badFrac, pmSubtractionMode subMode)
 {
     if (subMode != PM_SUBTRACTION_MODE_2) {
@@ -167,4 +167,8 @@
     PS_ASSERT_INT_POSITIVE(iter, false);
     PS_ASSERT_FLOAT_LARGER_THAN(rej, 0.0, false);
+    if (isfinite(sysError)) {
+        PS_ASSERT_FLOAT_LARGER_THAN_OR_EQUAL(sysError, 0.0, NULL);
+        PS_ASSERT_FLOAT_LESS_THAN(sysError, 1.0, NULL);
+    }
     // Don't care about maskVal
     // Don't care about maskBad
@@ -393,5 +397,5 @@
             psTrace("psModules.imcombine", 2, "Convolving...\n");
             if (!pmSubtractionConvolve(conv1, conv2, ro1, ro2, subMask, maskBad, maskPoor, poorFrac,
-                                       region, kernels, true, useFFT)) {
+                                       sysError, region, kernels, true, useFFT)) {
                 psError(PS_ERR_UNKNOWN, false, "Unable to convolve image.");
                 goto MATCH_ERROR;