how to fix IE "Page Has Expired error"

how to fix ie "Page Has Expired error":

 we have to use this following php header on page with is getting expired on the IE6>.

$datedisplay =  date("D, d M Y H:i:s", mktime(date(H)+1, 0, 0,date(m) , date(d), date(Y)));
$datedisplay .=" GMT";
header("Expires: $datedisplay"); // Always expired
header("Last-Modified: $datedisplay");// always modified
header("Cache-Control: cache, must-revalidate");// HTTP/1.1
header("Pragma: cache");// HTTP/1.0

i hope it will help u out..