Index: trunk/psModules/src/imcombine/pmSubtractionMatch.c
===================================================================
--- trunk/psModules/src/imcombine/pmSubtractionMatch.c	(revision 24257)
+++ trunk/psModules/src/imcombine/pmSubtractionMatch.c	(revision 24259)
@@ -379,5 +379,5 @@
                                 badFrac, subMode);
     if (!subMask) {
-        psError(PS_ERR_UNKNOWN, false, "Unable to generate subtraction mask.");
+        psError(psErrorCodeLast(), false, "Unable to generate subtraction mask.");
         goto MATCH_ERROR;
     }