Index: trunk/psModules/src/imcombine/pmSubtractionStamps.c
===================================================================
--- trunk/psModules/src/imcombine/pmSubtractionStamps.c	(revision 23791)
+++ trunk/psModules/src/imcombine/pmSubtractionStamps.c	(revision 23792)
@@ -373,5 +373,5 @@
     FILE *outFile = fopen(filename, "w"); // File to write
     if (!outFile) {
-        psError(PS_ERR_IO, false, "Unable to open %s for writing");
+        psError(PS_ERR_IO, false, "Unable to open %s for writing", filename);
         return false;
     }