Issues with namespaces and Migrate module migrating XML content
A few things had to be changed.

public function &amp;xml() {
    if (!empty($this-&gt;currentUrl)) {

      // $this-&gt;currentXml = simplexml_load_file($this-&gt;currentUrl);

      // simplexml_load_file wasn't explicit enough, change to file_get_contents
      // then explicitly call it a new SimpleXmlElement.

      $xml = file_get_contents($this-&gt;currentUrl);
      $this-&gt;currentXml = new SimpleXmlElement($xml);

      if (!$this-&gt;currentXml) {
        Migration::displayMessage(t(
          'Loading of !currentUrl failed:',
          array('!currentUrl' =&gt; $this-&gt;currentUrl)
        ));
        foreach (libxml_get_errors() as $error) {
          Migration::displayMessage(self::parseLibXMLError($error));
        }
      }
      else {
        $this-&gt;registerNamespaces($this-&gt;currentXml);
      }
    }

    return $this-&gt;currentXml;
  }


However, the major issue was this function in xml.inc:

protected function getElementValue($itemXML, $xpath) {
    $value = NULL;
    if ($itemXML) {
      $result = $itemXML-&gt;xpath($xpath);
      if ($result)
        $value = (string)$result[0];
    }
    return $value;
  }


The if($itemXML) needs to be changed to if($itemXML->asXML()), like so:

protected function getElementValue($itemXML, $xpath) {
    $value = NULL;
    if ($itemXML-&gt;asXML()) {
      $result = $itemXML-&gt;xpath($xpath);
      if ($result)
        $value = (string)$result[0];
    }
    return $value;
  }


After applying the patch manually and changing the simplexml_load_file and the if statement in the above functions, the import works successfully with namespaces.

I re-rolled the patch mentioned earlier with my changes: https://drupal.org/comment/8260027#comment-8260027