class not found exception

  Hello Postgresql users,
          I wrote a normal java application(using main() method) and
successfully connected to postgresql database but when I connect to it
using JSP, Iam getting 'Class not found exception'.Iam using pg73jdbc1.jar and jdk1.4.1_04 and Red Hat Linux 9.0.The web server is
Jakarta Tomcat 5.0.4.Please help me.Send a reply as soon as possible.


    M.Vijaya Raghava