User config

I am attempting to install IsaViz on one of our servers, with
the intention that I should set up some defaults (web browser,
location of dot executable) which should apply to all of the
users. I have tried editing the isaviz.cfg file in
the IsaViz home directory, but unfortunately

i) this appears to have no effect at all, and
ii) when I start IsaViz for the first time, it stores,
in my home directory, an isaviz.cfg file like this:

<?xml version="1.0" encoding="UTF-8"?>
<isv:config>
     <isv:urls/>
</isv:config>

and the next time it starts up, it complains that the
prefix isv is not associated with a namespace.

Any thoughts?

Graham White