textproc/xmlto: missing XML catalogs?

[Sergei Kolobov]

Hello,

I am trying to solve a little problem building a new port I just
submitted - textproc/xmlto (see ports/53173).

To quote its pkg-descr:
   "xmlto is a front-end to an XSL toolchain. It chooses an appropriate
   stylesheet for the conversion you want and applies it using an external
   XSL-T processor.  It also performs any necessary post-processing."

When building xmlto, I get a lot of warnings from xsltproc similar to this:
(manually wrapped for readability)

xmlNanoHTTPConnectAttempt: Connect attempt timed out.
/FreeBSD/current/ports/xmlto-0.0.14/xmlto-0.0.14/./doc/xmlif.xml:4: 
error: failed to load external entity 
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"

(also, the build time is greatly increased because of this timeouts).
Even though the port successfully builds despite the warnings, I am
trying to find out a better way. ;)

The port's homepage (http://www.cyberelk.net/tim/xmlto/) has the
following in the Problems section:

   Attempt to load network entity ... failed to load external entity
	This is caused by the absence of correctly configured XML
	Catalogs on your system. When XML Catalogs are available, URLs
	are transformed into local file references. For more information
	about XML Catalogs see the xsltproc documentation.

Unfortunately, I am a novice in XML area, so I am lost as to where to
get those XML catalogs.

I have the following DocBook- and XML-related ports installed:

docbook-1.2         Meta-port for the different versions of the DocBook DTD
docbook-241         V2.4.1 of the DocBook DTD, designed for technical documenta
docbook-3.0         V3.0 of the DocBook DTD, designed for technical documentati
docbook-3.1         V3.1 of the DocBook DTD, designed for technical documentati
docbook-4.0         V4.0 of the DocBook DTD, designed for technical documentati
docbook-4.1         V4.1 of the DocBook DTD, designed for technical documentati
docbook-xml-4.2     XML version of the DocBook DTD
docbook-xsl-1.61.2  XSL DocBook stylesheets
expat-1.95.6_1      XML 1.0 parser written in C
fontconfig-2.2.0    An XML-based font configuration API for X Windows
jade-1.2.1_1        An object-oriented SGML/XML parser toolkit and DSSSL engine
libxml2-2.5.7_1     Xml parser library for GNOME
sdocbook-xml-4.1.2.5 "Simplified" DocBook XML DTD
sgmlformat-1.7_2    Generates groff and HTML from linuxdoc and docbook SGML doc
xmlto-0.0.14        Front-end to an XSL toolchain

Am I missing something obvious? 
FWIW, the RPM spec file included with xmlto lists docbook-dtds as
dependency. What is its equivalent in ports? 

Thanks.

Sergei