Fatal error: Cannot redeclare class mysqldb in C:\Vasp\site&

N�o sei mais o que fazer quando eu chamo http://quarto/index1.php d� esse erro. Dentro do index1.php tenho o include

<? ini_set('arg_separator.output','&'); include("include/session.php"); include("query.php"); require("funcao.php");?>

e session.php tem

<?include("database.php");include("mailer.php");include("form.php");class Session{..................$session = new Session;$form = new Form;?>

alguma sugest�o ?