Setup differences php 5.2 and 5.3

I have a php that generates a XML file. It begins with the following code:

header("Content-Type: text/xml; charset=UTF-8");
header('Content-Disposition: attachment; filename="FileName.xml"');

// Outputs a lot o开发者_开发百科f XML

When I'm running PHP 5.2 it works fine, but on 5.3 an empty file is generated. Any ideas about why it's empty?

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this sounds like it could be related to short open tags functionality: <? vs <?php?

make sure you have short open tags disabled in your php.ini. if you need it activated, there's a workaround: for <?xml tag, wrap it in a string and echo it, so it will not be interpreted as the start of a php block by php

echo '<?xml … >';