Hello Pratheeba,
I was trying out an example in the book Professional Java Server Programming J2EE Edition (Chapter 11, beans useBean example) and I experienced the same problem as you. I found the solution in the Tomcat buglist (
http://nagoya.apache.org/bugzilla), bug# 10714. The problem is that the compiler looks for your SimpleBean in the jsp package and cannot find it there. The workarounnd suggested in a comment on this bug does not work, because you must also add a package name in an import directive. So you must put your SimpleBean in a package and specify it in the useBean action, e.g. class="MyPackage.SimpleBean".
Eugenio