404 not found error

[Eric Boo]

Hi all,
I have a virtual hostname a.b.com 
the files are in /var/tomcat/webapps/a

inside the directory a, there are other directories that contain jsp
files
if i go to http://a.b.com anc click on a link that leads to
http://a.b.com/here/main.jsp, it gives me a 404 (Not found) error


I'm using Apache + Tomcat 
How do I configure Tomcat so it reads the subdirectories correctly?

Eric