Header errors.

rltamm

<?php

//prevents caching
header("Expires: Sat, 01 Jan 2000 00:00:00 GMT");
header("Last-Modified: ".gmdate("D, d M Y H:i:s")." GMT");
header("Cache-Control: post-check=0, pre-check=0",false);
session_cache_limiter();

session_start();

require('config.php');
require('functions.php');
//this is group name or username of the group or person that you wish to allow access to
// - please be advise that the Administrators Groups has access to all pages.
if (allow_access(Administrators) != "yes")
{ 
include ('no_access.html'); 
exit;
}
?>

This is the code asked to put in HEAD of page.... i get errors...

Warning: Cannot modify header information - headers already sent by (output started at /home/content/76/8773476/html/eahtml/studentcenter.php:1) in /home/content/76/8773476/html/eahtml/studentcenter.php on line 4

Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /home/content/76/8773476/html/eahtml/studentcenter.php:1) in /home/content/76/8773476/html/eahtml/studentcenter.php on line 9

if i remove the header info.... i just get a loop and no actual log in to access page... any help would be great'

Weedpacket

From the manual page for [man]header[/man]:

Remember that header() must be called before any actual output is sent, either by normal HTML tags, blank lines in a file, or from PHP. It is a very common error to read code with include, or require, functions, or another file access function, and have spaces or empty lines that are output before header() is called. The same problem exists when using a single PHP/HTML file.

This also includes byte-order-marker symbols some text editors stick at the beginning of Unicode-encoded text files (the text editor then hides the BOM when displaying the file). Whether this is the case here and what to do about it if it is depends on your text editor.

You can also try writing the file directly to the terminal window to see how it starts, and you can also try using the browser to look at what exactly it receives from the server (view page source, or even look at the raw response.)