Jetty (and Tomcat6 before) doesn't see Gnizr

[cococom]

Hello,
I spent a lot of time trying installing Gnizr in the default Jetty's
depository webapps and before with a Tomcat6 server but the problem is
always the same : a 404 error status and the following message : the
ressource is not available.
However, I followed the tutorial for the database configuration and
customized the default file configuration as indicated.
I've never work before with a java web application and perhaps I
skipped a stage in the installation procedure but as the on line gnizr
documentation is a little bit yet light, could you help me because I
don't see what else I could do ...
Thanks in advance

Cococom

OS : Linux Ubuntu 8.04 Hardy (KDE graphic interface, i.e. Kubuntu)
Java server : Jetty
Jetty default page is working on http://localhost:8080/