se faccio cosi':


if(!session_is_registered('Tipo') && !empty($HTTP_POST_VARS["submit"]) )
{
session_start();

$_SESSION["Tipo"]=$Tipo;
$Tipo=$HTTP_POST_VARS["submit"];
echo($Tipo);
}
mi da il seguente errore che non riesco a capire:
Warning: Unknown(): Your script possibly relies on a session side-effect which existed until PHP 4.2.3. Please be advised that the session extension does not consider global variables as a source of data, unless register_globals is enabled. You can disable this functionality and this warning by setting session.bug_compat_42 or session.bug_compat_warn to off, respectively. in Unknown on line 0

cosa puo' essere?