come mai ricevo quest'errore?
Warning: session_start(): Cannot send session cookie - headers already sent by (output started at c:\programmi\easyphp1-8\www\ecommerce\index.php:8) in c:\programmi\easyphp1-8\www\ecommerce\index.php on line 9

Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at c:\programmi\easyphp1-8\www\ecommerce\index.php:8) in c:\programmi\easyphp1-8\www\ecommerce\index.php on line 9
4746120573c5d7abcdf139096193789b

il codice è questo:
<?
session_start();
$id=session_id();
echo $id
?>
grazie
(ps: uso easyphp 1.8