Bundle::XML was the first package to be installed

That might be the problem. I think the latest version of XML::DOM can be found in libxml-enno. I have no idea which one is included in the XML bundle. The only stable combination I have personally tested is XML::DOM 1.25 and XML::Parser 2.27 on Perl 5.005.

Note that the original author of XML::DOM does not seem to be supporting it anymore and that a new maintainer seems to be working on it, see this message. One annoying thing is that the old version does not work with XML::Parser 2.28 and above but the new version does not work with 2.27 and under (2.27 is the one that comes with the Activestate port).

If you are interested in Perl and XML you should definitely subscribe to the perl-xml mailing list.