Generated XML with PHP can't render in LINUX

I define multiple XML file for my website sitemap. One of them generated dynamically.

This file correctly render on windows (My OS :( ) and also on windows server (local server OS) as below:

<urlset xmlns="http://ift.tt/xwbjRF">
    <url>
        <loc>http://ift.tt/1rWv0gC;
        <lastmod>2014-08-02</lastmod>
        <changefreq>hourly</changefreq>
        <priority>0.7</priority>
    </url>

    <url>
        <loc>http://ift.tt/1rZaH5G;
        <lastmod>2014-08-02</lastmod>
        <changefreq>hourly</changefreq>
        <priority>0.7</priority>
    </url>
    ...
    ...

But when I upload my codes on Linux server(centOS), this page is just blank white page.

My PHP code to generate this XML is:

<?php
header('Content-type: application/xml');
if(isset($_GET['type']))
    $type = $_GET['type'];
else
    $type = 'category';
require_once '/protected/PDODB.php';
// configuration
switch ($type)
{
    case 'category':
        $sql = 'SELECT id,ename FROM tbl_category WHERE status=0';
        $priority = 0.7;
        $changefreq = 'hourly';
        break;
    case 'group':
        $sql = 'SELECT gr.id groupId, gr.ename groupName, cat.id catId, cat.ename catName '.'FROM tbl_group gr, tbl_category cat WHERE gr.status=0';
        $priority = 0.6;
        $changefreq = 'hourly';
        break;
    case 'object':
        $sql = 'SELECT name,code,time FROM tbl_object WHERE status=0';
        $priority = 0.5;
        $changefreq = 'daily';
        break;
    default:
        $sql = 'SELECT id,ename FROM tbl_category WHERE status=0';
        $priority = 0.7;
        $changefreq = 'hourly';
        break;
}

?>
<?xml version="1.0" encoding="UTF-8"?>
    <urlset xmlns="http://ift.tt/xwbjRF">
        <?PHP foreach ($dbh->query($sql) as $row): ?>
        <url>
            <loc>
                <?PHP if($type == 'category'): ?>
                    http://ift.tt/1rWuXBt echo $row['ename']; ?>/CTG-<?PHP echo $row['id']; ?>
                <?PHP elseif($type == 'group'): ?>
                    http://ift.tt/1rWuXBt echo $row['catName']; ?>/<?PHP echo $row['groupName']; ?>/<?PHP echo $row['catId']; ?>-<?PHP echo $row['groupId']; ?>
                <?PHP elseif($type == 'object'): ?>
                    http://ift.tt/1rZaH5I echo $row['code']; ?>
                <?PHP endif; ?>
            </loc>
            <lastmod>
                <?PHP if($type == 'object'): ?>
                <?PHP echo date('Y-m-d', $row['time']); ?>
                <?PHP else: ?>
                <?PHP echo date('Y-m-d', time()); ?>
                <?PHP endif; ?>
            </lastmod>
            <changefreq><?PHP echo $changefreq; ?></changefreq>
            <priority><?PHP echo $priority; ?></priority>
        </url>
        <?PHP endforeach; ?>
    </urlset>  

Could you please tell me where is the problem?

Any help will be appreciated.