External instance data that references a DTD prompts a 'DTD Prohibited' message

In the 'IPTC Codes' sample form in public SVN repository, the intance data contained in iptc-genre.xml references the DTD, NewsMLv1.0.dtd. When running the SVN_HOME\samples\fpdotcom\object\iptc-newsubjectviewer\index.html file there is a xforms-link-exception popup saying that 'could not connect...' to the iptc-genre.xml file. This file exists and is well formed. Clicking 'Cancel' gives the following message:

Failed to load instance "#",
Reason:DTD is prohibited.
at:(null)

The message 'DTD is prohibited' seems to be related to MSXML 6. See MSDN link.