Spreadsheet error al abrir un libro excel

Este es el principio del Controller donde da el problema
class DocumentosController < ApplicationController
require “spreadsheet/excel”
include Spreadsheet

GET /documentos

GET /documentos.xml

def exportar
@documento = Documento.find(params[:id])

# Create workbook
file = "FC_VTA0015.xls"
workbook = Spreadsheet::ParseExcel.parse

("#{RAILS_ROOT}/public/excel/#{file}")
worksheet = workbook.worksheets[0]

# Datos del encabezado
worksheet.write(1,1, @documento.folio)
worksheetwriter(2,1, @documento.fecha)
worksheetwriter(3,1, @documento.sujeto.apellido)

y el log dice …

e[4;36;1mDocumento Columns (0.015000)e[0m e[0;1mSHOW FIELDS FROM
documentose[0m
e[4;35;1mDocumento Load (0.000000)e[0m e[0mSELECT * FROM documentos
WHERE (documentos.id = 1) e[0m

NameError (uninitialized constant Spreadsheet::ParseExcel):
c:/ruby/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:263:in
load_missing_constant' c:/ruby/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:452:inconst_missing’
/app/controllers/documentos_controller.rb:12:in exportar' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/base.rb:1095:insend’
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/base.rb:1095:in
perform_action_without_filters' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:632:incall_filter’
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:638:in
call_filter' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:438:incall’
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:637:in
call_filter' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:638:incall_filter’
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:438:in
call' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:637:incall_filter’
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:638:in
call_filter' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:438:incall’
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:637:in
call_filter' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:619:inperform_action_without_benchmark’
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/benchmarking.rb:66:in
perform_action_without_rescue' c:/ruby/lib/ruby/1.8/benchmark.rb:293:inmeasure’
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/benchmarking.rb:66:in
perform_action_without_rescue' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/rescue.rb:83:inperform_action’
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/base.rb:430:in
send' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/base.rb:430:inprocess_without_filters’
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:624:in
process_without_session_management_support' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/session_management.rb:114:inprocess’
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/base.rb:330:in
process' c:/ruby/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/dispatcher.rb:41:indispatch’
c:/ruby/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/webrick_server.rb:113:in
handle_dispatch' c:/ruby/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/webrick_server.rb:79:inservice’
c:/ruby/lib/ruby/1.8/webrick/httpserver.rb:104:in service' c:/ruby/lib/ruby/1.8/webrick/httpserver.rb:65:inrun’
c:/ruby/lib/ruby/1.8/webrick/server.rb:173:in start_thread' c:/ruby/lib/ruby/1.8/webrick/server.rb:162:instart’
c:/ruby/lib/ruby/1.8/webrick/server.rb:162:in start_thread' c:/ruby/lib/ruby/1.8/webrick/server.rb:95:instart’
c:/ruby/lib/ruby/1.8/webrick/server.rb:92:in each' c:/ruby/lib/ruby/1.8/webrick/server.rb:92:instart’
c:/ruby/lib/ruby/1.8/webrick/server.rb:23:in start' c:/ruby/lib/ruby/1.8/webrick/server.rb:82:instart’
c:/ruby/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/webrick_server.rb:63:in
dispatch' c:/ruby/lib/ruby/gems/1.8/gems/rails-1.2.3 /lib/commands/servers/webrick.rb:59 c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:ingem_original_require’
c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
require' c:/ruby/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:495:inrequire’
c:/ruby/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:342:in
new_constants_in' c:/ruby/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:495:inrequire’
c:/ruby/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/commands/server.rb:39
c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
gem_original_require' c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:inrequire’
script/server:3

y yo que solo quiero poner unos datos en una planilla EXCEL, …
espero alguien sepa que es lo que hago mal.

gracias