Java compilation error

Hi

I compiled a java program using javax.servlet & it has
error as below :-

Pls help me what is the problem & what need to do
to solve the problem.
I'm using jdk1.3.1 & Apache Tomcat 4.0.1.

Thanks
Heng03

Compiling C:\Java_Project_2\WEB-INF\classes\CheckUser.java
C:\Java_Project_2\WEB-INF\classes\CheckUser.java:8: package javax.servlet does not exist
import javax.servlet.*;
^
C:\Java_Project_2\WEB-INF\classes\CheckUser.java:9: package javax.servlet.http does not exist
import javax.servlet.http.*;
^
C:\Java_Project_2\WEB-INF\classes\CheckUser.java:11: cannot resolve symbol
symbol  : class HttpServlet  
location: class CheckUser
public class CheckUser extends HttpServlet {
                               ^
C:\Java_Project_2\WEB-INF\classes\CheckUser.java:17: cannot resolve symbol
symbol  : class ServletConfig  
location: class CheckUser
     public void init(ServletConfig config) throws ServletException {