NoMethodError in Auto adminController#index

I’m a pretty big newbie with ROR, but when following a tutorial I
encounter an ugly error when building a scaffold. here is what am
getting the error while trying to execute the applicaton…

C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:376:in
new_constants_in' C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:202:inload_file’
C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:94:in
require_or_load' C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:248:inload_missing_constant’
C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:453:in
const_missing' C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:465:inconst_missing’
C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/inflector.rb:257:in
constantize' C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/core_ext/string/inflections.rb:148:inconstantize’
C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/routing.rb:1426:in
recognize' C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:170:inhandle_request’
C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:115:in
dispatch' C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:126:indispatch_cgi’
C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:9:in
dispatch' C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/webrick_server.rb:112:inhandle_dispatch’
C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/webrick_server.rb:78:in
service' C:/InstantRails/ruby/lib/ruby/1.8/webrick/httpserver.rb:104:inservice’
C:/InstantRails/ruby/lib/ruby/1.8/webrick/httpserver.rb:65:in run' C:/InstantRails/ruby/lib/ruby/1.8/webrick/server.rb:173:instart_thread’
C:/InstantRails/ruby/lib/ruby/1.8/webrick/server.rb:162:in start' C:/InstantRails/ruby/lib/ruby/1.8/webrick/server.rb:162:instart_thread’
C:/InstantRails/ruby/lib/ruby/1.8/webrick/server.rb:95:in start' C:/InstantRails/ruby/lib/ruby/1.8/webrick/server.rb:92:ineach’
C:/InstantRails/ruby/lib/ruby/1.8/webrick/server.rb:92:in start' C:/InstantRails/ruby/lib/ruby/1.8/webrick/server.rb:23:instart’
C:/InstantRails/ruby/lib/ruby/1.8/webrick/server.rb:82:in start' C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/webrick_server.rb:62:indispatch’
C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/commands/servers/webrick.rb:66
C:/InstantRails/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
gem_original_require' C:/InstantRails/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:inrequire’
C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:496:in
require' C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:342:innew_constants_in’
C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:496:in
require' C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/commands/server.rb:39 C:/InstantRails/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:ingem_original_require’
C:/InstantRails/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
`require’

You have a nil object when you didn’t expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.empty?

Please suggest me asap…