diff --git a/xmlsitemap.admin.inc b/xmlsitemap.admin.inc
index 2b34c02..2df030d 100644
--- a/xmlsitemap.admin.inc
+++ b/xmlsitemap.admin.inc
@@ -401,9 +401,9 @@ function xmlsitemap_settings_form_validate($form, &$form_state) {
     form_set_error('xmlsitemap_chunk_size', t('The sitemap page link count of @size will create more than 1,000 sitemap pages. Please increase the link count.', array('@size' => $chunk_size)));
   }
 
-  $base_url = &$form_state['values']['xmlsitemap_base_url'];
+  $base_url = $form_state['values']['xmlsitemap_base_url'];
   $base_url = rtrim($base_url, '/');
-  if ($base_url != '' && !valid_url($base_url, TRUE)) {
+  if (empty($base_url) || !valid_url($base_url, FALSE)) {
     form_set_error('xmlsitemap_base_url', t('Invalid base URL.'));
   }
 }