diff --git a/os/pl-error.c b/os/pl-error.c
old mode 100644
new mode 100755
index f3eb2f63b..8587a9198
--- a/os/pl-error.c
+++ b/os/pl-error.c
@@ -204,6 +204,11 @@ PL_instantiation_error(term_t actual)
 { return PL_error(NULL, 0, NULL, ERR_INSTANTIATION);
 }
 
+int
+PL_uninstantiation_error(term_t actual)
+{ return PL_error(NULL, 0, NULL, ERR_UNINSTANTIATION, 0, actual);
+}
+
 int
 PL_representation_error(const char *resource)
 { atom_t r = PL_new_atom(resource);