Checking login and redirecting to new header from an included part of the page causes header already sent error

Hey

Well the story is my index page calls a header, cell and footer. The cell being the changing element. I'm now adding member only pages and don't know how to protect the page from unauthorised access.

I use this..

<?php
session_start();
if( @$_SESSION['auth'] !="yes")
{header("Location: ../index.php?cellname=pagecells/noauth.php");
exit();
}
?>

and I call it at the start of the cell file that requires protection. Problem is I get errors regarding the header already being sent.

So any ideas on a better way to structure my page. I have offcourse considered sending logged in users to a new php file totally but once again I would want to use cells in that page. If those cell files exist back to square one they will simply be accessed view the original and free to access index.

Only option is whole range of pages created for users only!

thanks for any advice