diff --git a/org/qmckl_electron.org b/org/qmckl_electron.org
index a7164d7..af06ba3 100644
--- a/org/qmckl_electron.org
+++ b/org/qmckl_electron.org
@@ -304,7 +304,7 @@ qmckl_set_electron_coord(qmckl_context context,
 
   if (coord == NULL) {
     return qmckl_failwith( context,
-                           QMCKL_INVALID_ARG_3,
+                           QMCKL_INVALID_ARG_4,
                            "qmckl_set_electron_coord",
                            "coord is a null pointer");
   }