cannot load controller servlet

[Gopalakrishnan Rangaswamy]

Hi all

Iam trying to deploy a struts application on to tomcat which is running
fine on iplanet web server4.1.
The environment is 
tomcat-3.2.3 on Windows NT 4.0,

My application is named ddtsweb, iam giving the folder structure below
from webapps onwards

webapps
        !
        ddtsweb
                !
                WEB-INF
                        !
                        classes(folder containing classes and
servlets),struts-config.xml,web.xml
                        !
                        lib(this contains all the jars including
struts.jar)
when i run tomcat from bin, iam coninously getting message which is
"cannot load servlet name : action :null"

action is the name of the controller servlet.  The controller servlet is
take out of the struts.jar and it is inside a package in classes folder.

the database servlet is loading succesfully, it is inside struts.jar

any suggestions giving some direction will be helpful

thanks