diff --git a/bureau/admin/ip_main.php b/bureau/admin/ip_main.php
index 2d863ebb..33ee30e6 100644
--- a/bureau/admin/ip_main.php
+++ b/bureau/admin/ip_main.php
@@ -52,7 +52,7 @@ $lac = $authip->list_affected();
 <br />
 
 <?php if (isset($error) && $error) { ?>
-  <p class="error"><?php echo $error ?></p>
+  <p class="error"><?php echo $error ; $error=''; ?></p>
 <?php } ?>
 
 <p><?php __("Here you can add rules to restrict access to AlternC's services, filtered by IP. First, add trusted IPs in the 'Known IP and networks' list. Then, add rules to grant access on services to the chosen IPs from this list.") ?></p>
diff --git a/bureau/class/m_authip.php b/bureau/class/m_authip.php
index d6400594..ead2b312 100644
--- a/bureau/class/m_authip.php
+++ b/bureau/class/m_authip.php
@@ -319,14 +319,23 @@ class m_authip {
    * @return boolean Retourne TRUE
    */
   function call_hooks($function, $affectation_id) {
-    global $hooks;
+    global $hooks,$err;
 
     // On récure l'objet dont on parle
     $d = $this->list_affected();
+    if (! isset($d[$affectation_id] )) {
+      $err->raise('authip', _("Object not available"));
+      return false;
+    }
+
     $affectation = $d[$affectation_id];
 
     // On en déduis la classe qui le concerne
     $e = $this->get_auth_class();
+    if (! isset($e[$affectation['protocol']])) {
+      $err->raise('authip', sprintf(_("Can't identified class for the protocole %s"), $affectation['protocol']));
+      return false;
+    }
     $c = $e[$affectation['protocol']]['class'];
 
     // On appelle le hooks de cette classe