gtk-doc installation error "configure: error: could not find DocBook XML DTD V4.3 in XML catalog"

[Peng Yu]

I always get this error. Does anybody know how to fix the error and
install gtk-doc?

$ sudo port -d install gtk-doc

.....

checking for DocBook XML DTD V4.3 in XML catalog... not found
configure: error: could not find DocBook XML DTD V4.3 in XML catalog
shell command " cd
"/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_ports_gnome_gtk-doc/work/gtk-doc-1.17"
&& ./configure --prefix=/opt/local
--with-xml-catalog=/opt/local/etc/xml/catalog " returned error 1
Error: Target org.macports.configure returned: configure failure:
shell command failed (see log for details)
DEBUG: Backtrace: configure failure: shell command failed (see log for details)
    while executing
"$procedure $targetname"
Warning: the following items did not execute (for gtk-doc):
org.macports.activate org.macports.configure org.macports.build
org.macports.destroot org.macports.install
Log for gtk-doc is at:
/opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_release_ports_gnome_gtk-doc/main.log
Error: Status 1 encountered during processing.
To report a bug, see <http://guide.macports.org/#project.tickets>


-- 
Regards,
Peng