Hi, I have solved the issue. and also blog the steps which may help you to upgrade existing rails application to rails 3.x.
http://priyankapathak.wordpress.com/2010/12/13/upgrade-existing-ruby-on-rails-application-with-rails-3-0-0-and-ruby-1-9-2p0/ -- Posted via http://www.ruby-forum.com/. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-t...@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.