> Could any body  help me how am I able to use the
> search function of website offline download by this
> software?
Search functions, forms, and dynamic pages (cgi, asp, php, etc)  require
server side processing.  A mirror is a static copy. 

You have no web server, no database, just plain html files.  Answer, you
can't.  You can use the command line functions find and findstr, and the gui
search functions however.