Welcome to the JavaRanch. How are you building and deploying your application? Are you sure that your JAR dependencies are getting into your WAR file?
Have a look at the Tomcat Application Developers Guide for the best practices on building and deploying.
I am using eclipse.
Created Dynamic webproject.
Copied all required jar files into lib.
Copied required all tlds into WEB-INF.
Created struts-config.xml in WEB-INF.
Configured ActionServlet in web.xml.
Then i am running the application in tomcat from eclipse. I am creating war and deploying