Does anyone know where I can obtain the DTD for Tomcat 4.0.1's server.xml ?

Alessandro A. Garbagnati

The fact that there is no <!DOCTYPE> for that makes me think that there isn't a real DTD available for the server configuration file (server.xml).
The Tomcat 4.0 documentation site is still in development and many parts are still incomplete, but the configuration reference contains the explanation of all the different elements of the server.xml file and their attributes.