well it looks right to me. You should be hitting:
http://localhost:8080/chapterTwo/Name
Then that form hits:
/chapterTwo/HelloWorld
All your getters and setters are public and named correctly. So I don't see anything wrong here ... I would recommend to turn on trace, it seems your struts jars may not all be deployed correctly or you are missing something. Your packages extend struts-default but I have a feeling that something is from the struts2 jars is missing.