am getting Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent while running the following code. please help to fix it.. thanks.
<html>
<!-- centermain.php is a frame, user redirected to frame if tried to access from url-->
<SCRIPT LANGUAGE='javascript'>try { if (top == self) {top.location.href='centermain.php'; } } catch(er) { } </SCRIPT>
</html>
<?php
session_start();// initialize session
//code
?>