Problema Ao Ler Xml Com Dom

[senna]

ola galera to com pequeno probleminha ao ler um xml

o codigo é o seguinte

<?php
  $doc = new DOMDocument();
  $doc->load( 'host.xml' );
  
  $books = $doc->getElementsByTagName( "Hostip" );
  foreach( $books as $book )
  {
  $authors = $book->getElementsByTagName( "gml:name" );
  $author = $authors->item(0)->nodeValue;
  
  $publishers = $book->getElementsByTagName( "countryName" );
  $publisher = $publishers->item(0)->nodeValue;
  
  $titles = $book->getElementsByTagName( "countryAbbrev" );
  $title = $titles->item(0)->nodeValue;
  
  echo "$title - $author - $publisher\n";
  }
  ?>

eu peguei ele em http://www-128.ibm.com/developerworks/open...y/os-xmldomphp/ (ae nem renomiei as variaveis nem nada) e to tentando adapta pra outro xml, só q a informação q eu mais queria pegar dele não to conseguindo q é a parte "gml:name", as outras porem são impressas, aqui vai um xml q eu to tentando ler.

<?xml version="1.0" encoding="ISO-8859-1" ?>
<HostipLookupResultSet version="1.0.0" xmlns="http://www.hostip.info/api" xmlns:gml="http://www.opengis.net/gml" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.hostip.info/api/hostip-1.0.0.xsd">
 <gml:description>This is the Hostip Lookup Service</gml:description>
 <gml:name>hostip</gml:name>
 <gml:boundedBy>
  <gml:Null>inapplicable</gml:Null>
 </gml:boundedBy>
 <gml:featureMember>
  <Hostip>
   <gml:name>Sugar Grove, IL</gml:name>
   <countryName>UNITED STATES</countryName>
   <countryAbbrev>US</countryAbbrev>
   <!-- Co-ordinates are available as lng,lat -->
   <ipLocation>
    <gml:PointProperty>
     <gml:Point srsName="http://www.opengis.net/gml/srs/epsg.xml#4326">
      <gml:coordinates>-88.4588,41.7696</gml:coordinates>
     </gml:Point>
    </gml:PointProperty>
   </ipLocation>
  </Hostip>
 </gml:featureMember>
</HostipLookupResultSet>

acredito q seja algum problema com o ":" se puderem dar um help