Index: trunk/psModules/src/imcombine/pmStack.c
===================================================================
--- trunk/psModules/src/imcombine/pmStack.c	(revision 26260)
+++ trunk/psModules/src/imcombine/pmStack.c	(revision 27004)
@@ -1008,5 +1008,5 @@
     if (!pmReadoutStackValidate(&minInputCols, &maxInputCols, &minInputRows, &maxInputRows, &xSize, &ySize,
                                 stack)) {
-        psError(PS_ERR_UNKNOWN, false, "Input stack is not valid.");
+        psError(psErrorCodeLast(), false, "Input stack is not valid.");
         psFree(stack);
         return false;