http status 500 - Child of an Engine must be a Host

[jdware]

Hi all,
    I get this error when trying to access my struts app over an
intranet using just  IP:port/context rather than hostname:port/context.
I'm using struts source( ~4/13), tomcat 4.0-b1 standalone.
This is a new one to me.

thanks

john ware