Right now the DwC Terms RDF download at http://rs.tdwg.org/dwc/rdf/dwcterms.rdf sets the namespace URI to http://rs.tdwg.org/dwc/terms/ and doesn't seem to otherwise mention the download URI.
I may be missing something, but doesn't that mean that DwC Terms referenced in RDF documents using the canonical namespace URI (http://rs.tdwg.org/dwc/terms/ ) can't be resolved?
I guess at present that doesn't matter too much as there isn't really anything in the DwC Terms ontology that would tell a client agent something about the term that it wouldn't already know. But it's maybe worth noting that that's different from other well-known vocabularies. For example, the canonical URI for DC Terms (http://purl.org/dc/ terms/) resolves to the RDF for the whole vocabulary.
(BTW I'm not sure this is the right list to post DwC questions/issues to - let me know if it's not and where to send instead)
-hilmar