diff --git a/onyx/include/admin/import_exercices.php b/onyx/include/admin/import_exercices.php
index 9471d913..79592a4a 100644
--- a/onyx/include/admin/import_exercices.php
+++ b/onyx/include/admin/import_exercices.php
@@ -40,7 +40,7 @@ if ($SESS->level > 1)
       {
 	$ex = new Exercice();
 
-	$ex->id = $element->getAttribute("id");
+	$ex->id = preg_replace("/[^a-zA-Z0-9_]/g", "_", $element->getAttribute("id"));
 	$ex->level = $element->getAttribute("level");
 	if ($element->hasAttribute("depends"))
 	  $ex->require = $element->getAttribute("depends");