PHP with XHTML MP 1.2

I have the following code: index.php

<?xml version="1.0" ?>
<!DOCTYPE html PUBLIC "-//WAPFORUM//DTD XHTML Mobile 1.2//EN"
        "http://www.openmobilealliance.org/tech/DTD/xhtml-mobile12.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>test</title>
        <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
        <meta content="metadesc" name="description" />
        <meta content="metakey" name="keywords" />
        <meta name ="googlebot" content="index,follow" />
        <meta name="robots" content="INDEX, FOLLOW" />
        <link rel="stylesheet" href="core.css"/>
</head>
<body>

<div class="page">
    <div class="head">
        <div class="menu">
            <ul>
                <li><a href="test.php?sid=<?php echo $id; ?>">test</a></li>
                <li><a href="test.php?sid=<?php echo $id; ?>">test</a></li>
                <li><a href="test.php?sid=<?php echo $id; ?>">test</a></li>
                <li><a href="test.php?sid=<?php echo $id; ?>">test</a></li>
                <li><a href="test.php?sid=<?php echo $id; ?>">test</a></li>
            </ul>
        </div>
    </div>  
</div>

</body>
</html>

my only issue is that when i try and preview the document, nothing shows no source code, no error or anything.

I have tried with the following in the header before any content to try and rectify the issue as i have looked and mobile xhtml can't be served as text/html. I have tried the following (obveously not at the same time):

<?php header("Content-type: application/xml ");?>

<?php header("Content-type: application/xhtml+xml ");?>

<?php header('Content-type: application/vnd.wap.xhtml+xml'); ?>

Still no output/errors or anything. Anyone any advise on what the issue could be?

Solution

Well it turned out display errors was off and i was getting a http 500 error in php as short tags wasn't turned off and it was trying to parse the <? in the xml