Hi, thank you chucre, but this not is the solution, the session.auto_start is On, I don't need use session_start() because it is automatic. This is my script: <? include_once 'usuario.class.php'; include_once 'carrito.class.php'; //session_start(); if (!session_id()) { session_start(); } if (!isset($_SESSION["ocarrito"])){ $_SESSION["ocarrito"] = new carrito(); } if (!isset($_SESSION["elusuario"])){ $_SESSION["elusuario"] = new usuario(); } ?> for your class work, is necessary verify the session_id, like this: if (!session_id()) session_start(); 2007/1/5, deinet < <mailto:lista_php@xxxxxxxxxx> lista_php@xxxxxxxxxx>: Hello list, i have a problem with sessions and class. I used to work with a server with session.auto_start=Off, and now I had to move all my sites to another server with session.auto_start=On, and I have this problem with the session: Fatal error: Unknown(): The script tried to execute a method or access a property of an incomplete object. Please ensure that the class definition carrito of the object you are trying to operate on was loaded _before_ the session was started in <archive> on line 43 The problem is the class is charged after the beginning of the session, but I don't know what to do to make it work, please help me. P.D.: To put the session.auto_start in Off is not a solution because the servers administrators don't admit that. I hope you will understand my problem, sorry for my english. Thank you very much, Carlos. -- Fernando Chure PSL/CE