Got internal servlet error with tomcat's example

[Dave]

Hi all,

I was testing my tomcat installation using examples from the package,
I had no problem in running the examples using the set-up from
mod_jk.conf-auto, which use "Alias" to set-up "/examples" in my
default web root.  

However, when I setup another vertualhost, I got internal servlet
error.  I was using the same "examples", it shouldn't be a programming
error.

Here is my setup of VH

        httpd.conf--->

<VirtualHost 192.168.0.5>
ServerName jsp
DocumentRoot "/www/examples"
JkMount /*.jsp apj13
JkMount /servlet/* apj13
........
</VirtualHost>

        server.xml --->

<Host "jsp">
    <Context path=""
        docBase="/www/examples" debug="0">
</Host>

Any idea? CLASSPATH? TOMCAT_HOME?

Thanks
Dave