Install gimp-user-manual fails

[David Rowe]

markd at macports.org wrote:
> But the gimp-user-manual port should not have this problem, and I didn't. 
> Have you done a selfupdate so that gimp-user-manual-0.12 is available?  Is
> docbook-xml-4.1.2 installed?  Does the file ${prefix}/etc/xml/catalog
> exist?
>
> Mark
>   
The answer is yes to all questions

I have just done a selfupdate and gimp-user-manual-0.12  is what I am 
trying to install.
docbook-xml-4.1.2 is installed and active
the file /opt/local/etc/xml/catalog does exist. ls -l gives:
-rw-r--r--   1 root  admin   911 Jun  9 16:31 catalog.

I am trying out PortAuthority and as far as I can see all the Build 
dependencies are present - except that I had gimp activated rather than 
gimp2. I fixed that but it still made no difference

I also tried Baz's suggestion of setting 
XML_CATALOG_FILES=/opt/local/etc/xml/catalog
but I still get the same error reports:
--------------------------------------------
sudo port install gimp-user-manual
Password:
--->  Building gimp-user-manual with target all
Error: Target com.apple.build returned: shell command " cd 
"/opt/local/var/db/dports/build/_opt_local_var_db_dports_sources_rsync.rsync.darwinports.org_dpupdate_dports_graphics_gimp-user-manual/work/gimp-help-2-0.12" 
&& make all " returned error 2
Command output: -- Building HTML for cs
I/O error : Attempt to load network entity 
http://docbook.sourceforge.net/release/xsl/current/xhtml/chunk.xsl
warning: failed to load external entity 
"http://docbook.sourceforge.net/release/xsl/current/xhtml/chunk.xsl"
compilation error: file 
/opt/local/var/db/dports/build/_opt_local_var_db_dports_sources_rsync.rsync.darwinports.org_dpupdate_dports_graphics_gimp-user-manual/work/gimp-help-2-0.12/stylesheets/plainhtml.xsl 
line 7 element import
xsl:import : unable to load 
http://docbook.sourceforge.net/release/xsl/current/xhtml/chunk.xsl
make: *** [stamps/html.cs.stamp] Error 5
-------------------------------------------

Regards

David Rowe