Cookie checkbox problem

[klik]

Included within my login_results() function is the following code

	// Conditional cookie statement
	if($check == 'ON'){

	// Register the authorised login cookie!
	$auth = 1;
	setcookie("authorised", $auth, time() + (172800));
}

Included in my index.php page is the following

<?php

if (isset($_POST['submit']) && $_POST['submit'] == 'Login')
{
    login_results();
}

if (($_SESSION['LoggedIn'] == 1) || (isset($_COOKIE[authorised])))
{ 
    echo '
    Welcome <font color="#003366">' . $_SESSION['username'] . '</font> , you are logged in. <br><br>
    [<a href="?action=logout">Logout</a>]
    ';
	number_of_members();
} 
else
{ 
    login_form();
    number_of_members();

}

I am getting the following error.

Cannot modify header information - headers already sent by ......

And one more question. If I want to display the username, the session username variable will have expired. Will i have to store the username in the cookie also?

???

[Weedpacket]

You can't add new headers to a response (and that includes headers generated by setcookie) after you've already sent output to the client. Part of the error message you left out says which line of which script started the output.

Rearrange your code so that you don't generate any output before you start setting headers (it might be something as simple as deleting a stray blank line, or it might just be a matter of moving a chunk of HTML to somewhere lower down the page, or it might require a bit of thought about what the program is actually doing. Without seeing the code - or even a complete error message - it's impossible to tell which.)

For more information, search the forums with the text of your error message (headers already sent etc.) as the search term.