Tomcat generates errors in log file when loading servlets

[DP...@aol.com]

I have been trying to get a simple HelloWorld servlet to run for over a week 
now, and
I have been unable to make progress.  Although tomcat appears to start 
properly, when
I try to execute a simple servlet, nothing happens.  When I look at the 
localhost_admin_log
file, it appears that there are errors in instantiating the DefaultServlet.  
The following is part of
what is in the log file:

2003-03-04 12:37:13 StandardWrapper[/admin:default]: Loading container 
servlet default
2003-03-04 12:37:13 StandardWrapper[/admin:default]: Marking servlet default 
as unavailable
2003-03-04 12:37:13 StandardContext[/admin]: Servlet /admin threw load() 
exception
javax.servlet.ServletException: Error instantiating servlet class 
org.apache.catalina.servlets.DefaultServlet
            ...
            ....
----- Root Cause -----
java.lang.NoClassDefFoundError

I am running tomcat 4.1.12, and all the variables CATALINA_HOME, JAVA_HOME, 
etc 
are set correctly.  Anybody have any ideas on how to fix this?  

Dom Pante
DPante@aol.com