Description:
------------
i think ob_start not work
try no appserv 2.4.7 and 2.5.7
windows xp with ajax frame work

Reproduce code:
---------------
// * ALL.php for Ahtoring
<?php
ob_start();
header('Content-Type: text/html; charset=utf-8');
define('CONTENTS', true);
include_once('dynamic/dynamic.php');
echo"\n<! window fragment>\n";

if(isset($_REQUEST['modules'])){
	$modules = $_REQUEST['modules'];
	if(isset($_REQUEST['file'])){
		include_once("dynamic/modules/$modules/".$_REQUEST['file']);
	}else{
		include_once("dynamic/modules/$modules/contents.php");
	}
}else{
	header("location : index.php");
}
/*
$error = $db->sql_error($result);
foreach ($error as $value) {
    echo "<br />$value\n";
}
*/
echo"\n<! window fragment>\n";
ob_end_flush();
?>

// login script
<?php
if (!defined('CONTENTS')) {
        die ('<div class="blockError">You can\'t access this file directly...</div>');
}

function form(){
?>
	<div align="center">
	  <form method="post" action="all.php?modules=Pitt_Accounts&op=login" onsubmit="return post(this ,'content');">
		<table>
		  <tr>
			<td colspan="2">&#3626;&#3617;&#3634;&#3594;&#3636;&#3585;&#3648;&#3586;&#3657;&#3634;&#3626;&#3641;&#3656;&#3619;&#3632;&#3610;&#3610;</td>
		  </tr>
		  <tr>
			<td>&#3594;&#3639;&#3656;&#3629;&#3648;&#3619;&#3637;&#3618;&#3585;:</td>
			<td><input name="username" type="text" size="15" maxlength="25" /></td>
		  </tr>
		  <tr>
			<td>&#3619;&#3627;&#3633;&#3626;&#3612;&#3656;&#3634;&#3609;:</td>
			<td><input name="user_password" type="text" size="15" maxlength="20" /></td>
		  </tr>
		  <tr>
			<td colspan="2">
			  <input type="submit" name="Submit" value="Submit" /> 
			  <input type="reset" name="Submit2" value="Reset" />
		  </td>
		  </tr>
		</table>
	  </form>
	</div>
<?php
}

function login(){
	global $db;
	$user = $_POST['username'];
	$passwd = $_POST['user_password'];

	$sql = "SELECT * FROM `pitt_accounts` WHERE  username ='$user'";
	$result = $db->sql_query($sql);
	$field = $db->sql_fetchrow($result);
	$pitt_uid = $field['user_id'];
	$adusr = $field['username'];

	$valid_user = strcmp($user, $adusr);
	$valid_passwd = strcmp(md5($passwd), $field['password']);
	if ($valid_user == 0 && $valid_passwd == 0) {
		/* &#3606;&#3657;&#3634;&#3594;&#3639;&#3656;&#3629;&#3612;&#3641;&#3657;&#3651;&#3594;&#3657;&#3649;&#3621;&#3632;&#3619;&#3627;&#3633;&#3626;&#3612;&#3656;&#3634;&#3609;&#3606;&#3641;&#3585;&#3605;&#3657;&#3629;&#3591; &#3648;&#3619;&#3634;&#3592;&#3632;&#3626;&#3619;&#3657;&#3634;&#3591; session
		pitt_uid &#3607;&#3637;&#3656;&#3648;&#3585;&#3655;&#3610;&#3619;&#3627;&#3633;&#3626;&#3612;&#3641;&#3657;&#3651;&#3594;&#3657;
		pitt_user &#3648;&#3585;&#3655;&#3610;&#3594;&#3639;&#3656;&#3629;&#3612;&#3641;&#3657;&#3651;&#3594;&#3657;
		pitt_group &#3648;&#3585;&#3655;&#3610;&#3585;&#3621;&#3640;&#3656;&#3617;&#3612;&#3641;&#3657;&#3651;&#3594;&#3657; */
		$ip = ''.getenv("REMOTE_ADDR").'';
		$time = 'sign in '.date("Y-m-d ,H:i").'';
		$sql="INSERT INTO `pitt_accounts_log` ( `user_id` , `sign` , `ip` ) VALUES ( '$pitt_uid', '$time', '$ip');";
		$db->sql_query($sql);
/* CSLOX &#3651;&#3594;&#3657; php V4.3.1
	&#3617;&#3637; BUG &#3652;&#3617;&#3656; SUBPORT output buffering
	1 &#3627;&#3657;&#3634;&#3617;&#3626;&#3656;&#3591;&#3586;&#3657;&#3629;&#3617;&#3641;&#3621;&#3585;&#3656;&#3629;&#3609; COOKIE / SESSION
	2 &#3648;&#3619;&#3637;&#3618;&#3591;&#3594;&#3639;&#3656;&#3629;&#3605;&#3633;&#3623;&#3649;&#3611;&#3619;&#3604;&#3657;&#3623;&#3618; ?
	3 &#3623;&#3656;&#3634;&#3591;&#3654; &#3626;&#3656;&#3591; chang Log &#3652;&#3611;&#3651;&#3627;&#3657;&#3604;&#3641;&#3604;&#3657;&#3623;&#3618;
*/
		setcookie('pitt_uid' ,$pitt_uid ,time()+2592000);
//		setcookie('pitt_group' ,$field['group'] ,time()+2592000);
		setcookie('pitt_user' ,$adusr ,time()+2592000);
		$_SESSION['pitt_group'] = $field['group'];
		$client++; setcookie("client[$client]", urlencode("window.parent.location='admin.php?session=".rand()."';"));
	}else{
		$client++; setcookie("client[$client]", urlencode("alert('&#3619;&#3627;&#3633;&#3626; &#3627;&#3619;&#3639;&#3629; &#3594;&#3639;&#3656;&#3629;&#3612;&#3641;&#3657;&#3651;&#3594;&#3657;&#3612;&#3636;&#3604;');"));
	}
}

switch($_REQUEST['op']){
	case 'login': {	login(); break;}
	case 'logout' : {
		setcookie('pitt_uid');
		setcookie('pitt_user');
		unset($_SESSION['pitt_group']);
		$client++; setcookie("client[$client]", urlencode("window.parent.location='admin.php?session=".rand()."';"));
		break;
	}
	default : {	form();	}
}
?>

Expected result:
----------------
Warning: Cannot modify header information - headers already sent by (output started at C:\AppServ\www\SCT_CSS\all.php:1) in C:\AppServ\www\SCT_CSS\all.php on line 3
&#65279;&#65279;&#65279;
Warning: Cannot modify header information - headers already sent by (output started at C:\AppServ\www\SCT_CSS\all.php:1) in C:\AppServ\www\SCT_CSS\dynamic\modules\Pitt_Accounts\contents.php on line 68