diff --git a/admin/mnet/peer_forms.php b/admin/mnet/peer_forms.php
index b50f869c79d..5769e6de24c 100644
--- a/admin/mnet/peer_forms.php
+++ b/admin/mnet/peer_forms.php
@@ -61,7 +61,7 @@ class mnet_simple_host_form extends moodleform {
         if ($host = $DB->get_record('mnet_host', array('wwwroot' => $wwwroot))) {
             global $CFG;
             return array('wwwroot' => get_string('hostexists', 'mnet',
-                $CFG->wwwroot . '/' . $CFG->admin . '/mnet/peers.php?hostid=' . $host->id));
+                new moodle_url('/admin/mnet/peers.php', array('hostid' => $host->id))));
         }
         return array();
     }