Index: /trunk/psphot/src/psphot.c
===================================================================
--- /trunk/psphot/src/psphot.c	(revision 13477)
+++ /trunk/psphot/src/psphot.c	(revision 13478)
@@ -16,5 +16,8 @@
     // load command-line arguments, options, and system config data
     pmConfig *config = psphotArguments (argc, argv);
-    if (!config) usage ();
+    if (!config) {
+	psErrorStackPrint(stderr, "Error reading arguments\n");
+	usage ();
+    }
 
     // load input data (config and images (signal, noise, mask)