Simple Tapestry hello world example fails

I am following a book Enjoying web development with Tapestry.

The first chapter has a helloworld example where we create a Tapestry web project (say HelloWorld located at c:\Users\sachin\workspace\) in eclipse. The project has a home.html(located at c:\Users\sachin\workspace\HelloWorld\context\WEB-INF\), where I added the "Hello World" text in the body of the html. There are no other changes in the project. I now add a HelloWorld.xml in apache-tomcat\conf\catalina\localhost\

The contents of HelloWorld.xml are

<Context
docBase="c:/Users/sachin/workspace/HelloWorld/context"
path="/HelloWorld"/>

I deploy the project by starting the apache tomcat server manually.

Next I open the browser and type "http://localhost:8080/" which works fine.

Then I change the above URL to "http://localhost:8080/HelloWorld/app?service=page/Home" or "http://localhost:8080/HelloWorld", and my application fails to launch by giving the following error
----------------------------------------------------------------------------------
HTTP Status 404 - Servlet HelloWorld is not available

type Status report

message Servlet HelloWorld is not available

description The requested resource (Servlet HelloWorld is not available) is not available.
Apache Tomcat/6.0.24
--------------------------------------------------------------------------------------------------------------
My JDK is 1.6.

Any help in solving this issue shall be appreciated.