docbook xae problem

[Hans Steinraht <hans@artofakt.com>]

hi,

I'm just starting with docbook and for that I have installed xae on emacs.
I followed the little tutorial that's in the doc's directory to make the
file shortbook.xml.

Now I want to parse the file with saxon's xslt-parser.
I use the following command: 
	java com.icl.saxon.StyleSheet shortbook.xml
		/usr/share/xae/doctypes/docbook/styles/docbook/html/docbook.xsl
	
where shortbook.xml is the xml-file I have made in xae, and the second
argument (/usr/share/xae/doctypes/docbook/styles/docbook/html/docbook.xsl)
is the path to the file that contains the docbook-stylesheet that is put
there with insttalling xae.

The error that I get is:
	Error on line 3 column 120 of 
	file:/home/hans/development/saxon/docbookhs/src/test02/shortbook.xml:
  	Error reported by XML parser: Cannot read from
	file://usr/share/xae/doctypes/docbook/docbookx.dtd (usr)
	Transformation failed: Run-time errors were reported

I realy do not know what to do with this error, the path is right and I
don't think that there can be anything wrong with the permissions on that
file.
Saxon looks like working fine (Itried to transform some simple xml files
with simple stylesheets).

Can anyone give me some advice what to do.

Thanks,
Hans