With the paths now quoted (Thanks Daniel) the pdf file was created but the hyphenation patterns were irregular. To sort this out I replaced the contents of:
C:\Program Files\Syntext\Serna Free 4.4\xml\stylesheets\docbook-xsl-1.68.1\
with:
docbook-xsl-1.78.1
from sourceforge with out changing the original foldername
Also there is need for a folder docbookV4.5 in the directory of the xml file being published, with contents from docbook-xml-4.5
This is working from the command-line, and not the serna interface though.