Not enough information was provided for us to be able
to handle this bug. Please re-read the instructions at
http://bugs.php.net/how-to-report.php

If you can provide more information, feel free to add it
to this bug and change the status back to "Open".

Thank you for your interest in PHP.

As the documentation says at "http://www.php.net/manual/en/function.dom-domimplementation-createdocumenttype.php" the following code:

======================================================
<?php

// Creates an instance of the DOMImplementation class
$imp = new DOMImplementation;

// Creates a DOMDocumentType instance
$dtd = $imp->createDocumentType('graph', '', 'graph.dtd');

// Creates a DOMDocument instance
$dom = $imp->createDocument("", "", $dtd);

// Set other properties
$dom->encoding = 'UTF-8';
$dom->standalone = false;

// Create an empty element
$element = $dom->createElement('graph');

// Append the element
$dom->appendChild($element);

// Retrieve and print the document
echo $dom->saveXML();
?> 
======================================================

produces:

======================================================
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE graph SYSTEM "graph.dtd">
<graph/>
======================================================

So how can someone produce the following XML?

======================================================
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE graph SYSTEM "graph.dtd"[
    <!ENTITY testme "HELLO">
]>
<graph/>
======================================================

Sorry, but your problem does not imply a bug in PHP itself.  For a
list of more appropriate places to ask for help using PHP, please
visit http://www.php.net/support.php as this bug system is not the
appropriate forum for asking support questions.  Due to the volume
of reports we can not explain in detail here why your report is not
a bug.  The support channels will be able to provide an explanation
for you.

Thank you for your interest in PHP.