my $parser = XML::LibXML->new();
my $doc = $parser->parse_file($file);
my $t = $doc->getDocumentElement;
foreach my $node ($t->findnodes('TransactionList/Transaction/XML')) {
    my $xml = $node->firstChild;
my $xc = XML::LibXML::XPathContext->new($xml);
    foreach (qw( summary histFile fooScore )) {
        $xc->registerNs($_,"urn:$_");
        $node->setNamespace("urn:$_",$_,0);
    }
my $path = '//fooResponse/info/fooTransaction/transactionDetail/histFile:transactionSummary/summary:PacManScore';
my @nodes = $xc->findnodes($path);