no need to try to get files if we have no code

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(