Problem with pluto 1.1

Hi there!

I'm trying to embed Pluto in my own portal, but for the moment I'm having some 
trouble to get Pluto working on its own.

I've just installed Pluto 1.1 (with Java 1.5 and Tomcat 5.0.28) in Windows
and tried to load a portlet and I'm getting the following error when loading
http://localhost:8080/pluto/portal/HTML%20Viewer

null
The requested resource 
(/HTMLContentViewerPortlet/PlutoInvoker/HTMLContentViewerPortlet) is not 
available.

I've checked with Tomcat Manager that the webapp was running and the logs 
doesn't show anything relevant about it either.

Any idea about what's happening and how could I fix it?

Best regards