DOCBOOK-APPS: Pbs with website 2.3

[Thierry Nadal <thierry.nadal@ac-grenoble.fr>]

I'am trying to do a website with the norman walsh method, but i've got a pb
I can not resolve :

I have this error message : "this stylesheet relies on the exists ( )
extension function".

I do like this (as explained in the nwalsh site example) :
  1.. Create your webpages and your layout.xml file.

  2.. Use XSLT to create autolayout.xml. Do this by processing your
layout.xml with the autolayout.xsl stylesheet.

  3.. Use XSLT to build the website: process the autolayout.xml file with
the chunk-tabular.xsl stylesheet. That should build your website.

The error message appears after stage 3. I'm running a redhat 7.3

Could someone help me ??

Thank you,

Thierry Nadal