Niranjan, In the Struts config XML, SearchAction takes a SearchForm. Where is the form on index.jsp that is getting passed to it?
In the future (or for follow ups to this question), please post the relevant code snippets in the forum. It's a lot of steps to download this large zip file - which discourages people from looking at the problem.
In this case, the relevant files would be the XML and the index.jsp.
Your expception basically tells that the Form Bean has not been associated correctly with struts-config or it is not present in the classes folder. There may be some typos also which are the most un-noticable errors. This link gives a great refernce to the common struts errors. This should be helpful for common errors. http://www.geocities.com/Colosseum/Field/7217/SW/struts/errors.html.
If some problem exists, please post the JSP, action class adn struts-config. Regards, Roshani