If you just want the CDATA portion, there is really no point to use DOM. Instead, use XML::Parser or XML::Parser::Expat, and do something like this:

use XML::Parser::Expat;
use strict;

my $xml_string;
open(FOO, "test.xml") or die "failed to open";
local $/ = undef;
$xml_string = <FOO>;
close(FOO);

my $parser = new XML::Parser::Expat;
my $first;
$parser->setHandlers(CdataStart => \&start, 
                     CdataEnd => \&end
                    );
$parser->parse($xml_string);

sub start {
    $first = $_[0]->current_byte;
}

sub end {
    print substr($xml_string, $first, $_[0]->current_byte - $first + 1
+);
}
[download]