diff --git a/circ/set-library.pl b/circ/set-library.pl
index b03759be62..9d2823d9c6 100755
--- a/circ/set-library.pl
+++ b/circ/set-library.pl
@@ -76,7 +76,7 @@ if ( $branch and my $library = Koha::Libraries->find($branch) ) {
             old_desk => $old_desk_name,
         };
     }
-    if ( defined($userenv_register_id)
+    if ( defined($register_id)
         && ( $userenv_register_id ne $register_id ) )
     {
         my $old_register_name = C4::Context->userenv->{'register_name'} || '';
@@ -110,7 +110,7 @@ foreach ($query->param()) {
       };
 }
 
-my $referer =  $query->param('oldreferer') || $ENV{HTTP_REFERER};
+my $referer =  $query->param('oldreferer') || $ENV{HTTP_REFERER} || '';
 $referer =~ /set-library\.pl/ and undef $referer;   # avoid sending them back to this same page.
 
 if (scalar @updated and not scalar @recycle_loop) {