diff --git a/mobile.netbiblio.php b/mobile.netbiblio.php
index 356bc29..2df8867 100644
--- a/mobile.netbiblio.php
+++ b/mobile.netbiblio.php
@@ -250,6 +250,10 @@ class NetBiblio extends WebService
 
     private function AddFiles(array $book)
     {
+        if(!isset($book['code'])) {
+             return $book;
+        }
+
         $uri = sprintf("%s%s",
             Configuration::get('checkfile_url'),
             http_build_query(array(