问导致这个Rails方法错误的原因可能是什么？

EN

Processing OrganizationsController#search (for ::1 at 2010-05-13 15:42:01) [GET]
Parameters: {"action"=>"search", "controller"=>"organizations", "direction"=>"desc",     "_"=>"1273779721464", "order_by"=>"published_at"}
  SQL (0.5ms)   SHOW TABLES
  Organization Columns (2.2ms)   SHOW FIELDS FROM `organizations`

NoMethodError (undefined method `-@' for #<Array:0x2f88cc8>):
app/controllers/organizations_controller.rb:190:in `search'
sunspot (1.0.5) lib/sunspot/util.rb:84:in `call'
sunspot (1.0.5) lib/sunspot/util.rb:84:in `instance_eval_or_call'
sunspot (1.0.5) lib/sunspot/search.rb:200:in `build'
sunspot (1.0.5) lib/sunspot/session.rb:45:in `new_search'
sunspot (1.0.5) lib/sunspot/session.rb:53:in `search'
sunspot (1.0.5) lib/sunspot/session_proxy/abstract_session_proxy.rb:11:in `search'
sunspot (1.0.5) lib/sunspot.rb:323:in `search'
app/controllers/organizations_controller.rb:183:in `search'
haml (2.2.2) [v] rails/./lib/sass/plugin/rails.rb:19:in `process'
lib/flash_session_cookie_middleware.rb:14:in `call'
vendor/gems/hoptoad_notifier-2.2.2/lib/hoptoad_notifier/rack.rb:27:in `call'
/usr/local/lib/ruby/1.8/webrick/httpserver.rb:104:in `service'
/usr/local/lib/ruby/1.8/webrick/httpserver.rb:65:in `run'
/usr/local/lib/ruby/1.8/webrick/server.rb:173:in `start_thread'
/usr/local/lib/ruby/1.8/webrick/server.rb:162:in `start'
/usr/local/lib/ruby/1.8/webrick/server.rb:162:in `start_thread'
/usr/local/lib/ruby/1.8/webrick/server.rb:95:in `start'
/usr/local/lib/ruby/1.8/webrick/server.rb:92:in `each'
/usr/local/lib/ruby/1.8/webrick/server.rb:92:in `start'
/usr/local/lib/ruby/1.8/webrick/server.rb:23:in `start'
/usr/local/lib/ruby/1.8/webrick/server.rb:82:in `start'

Rendered rescues/_trace (68.5ms)
Rendered rescues/_request_and_response (0.6ms)
Rendering rescues/layout (internal_server_error)

s = Sunspot.search Organization do |query|
  query.with(:searchable).equal_to 'true'
  query.with(:updated_at).greater_than Time.zone.now-12.months
  query.paginate :page => (params[:page] && params[:page].to_i || 1), :per_page => 20
  query.keywords(params[:q]) { phrase_fields :quick_description => 3.0, :name => 3.0 } unless params[:q].blank?
  -# query.keywords(params[:q]) { phrase_fields :name => 3.0 } unless params[:q].blank?
  -# :name , :city
  query.order_by(params[:order_by], params[:direction] || 'asc') if params[:order_by] && params[:order_by] != 'distance'                 -# <-------- This is line 190 / this comment is not in the real code
  query.order_by('content_score', 'desc') if params[:q].blank?
end