undefined method `parse' for String:Class

Hi,

I use a script called : add_admin.rake When i execute this : 'rake -s -f Rakefile mailserv:add_admin --trace i have this error : ** Invoke mailserv:add_admin (first_time) ** Invoke environment (first_time) ** Execute environment ** Execute mailserv:add_admin rake aborted! undefined method `parse' for String:Class /usr/local/lib/ruby/gems/1.8/gems/highline-1.6.9/lib/highline/question.rb:329:in `convert' /usr/local/lib/ruby/gems/1.8/gems/highline-1.6.9/lib/highline.rb:268:in `ask' /var/mailserv/admin/lib/tasks/add_admin.rake:36 /usr/local/lib/ruby/gems/1.8/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `call' /usr/local/lib/ruby/gems/1.8/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `execute' /usr/local/lib/ruby/gems/1.8/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `each' /usr/local/lib/ruby/gems/1.8/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `execute' /usr/local/lib/ruby/gems/1.8/gems/rake-0.9.2.2/lib/rake/task.rb:158:in `invoke_with_call_chain' /usr/local/lib/ruby/1.8/monitor.rb:242:in `synchronize' /usr/local/lib/ruby/gems/1.8/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain' /usr/local/lib/ruby/gems/1.8/gems/rake-0.9.2.2/lib/rake/task.rb:144:in `invoke' /usr/local/lib/ruby/gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:116:in `invoke_task' /usr/local/lib/ruby/gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `top_level' /usr/local/lib/ruby/gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `each' /usr/local/lib/ruby/gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `top_level' /usr/local/lib/ruby/gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling' /usr/local/lib/ruby/gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:88:in `top_level' /usr/local/lib/ruby/gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:66:in `run' /usr/local/lib/ruby/gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling' /usr/local/lib/ruby/gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run' /usr/local/lib/ruby/gems/1.8/gems/rake-0.9.2.2/bin/rake:33 /usr/local/bin/rake:19:in `load' /usr/local/bin/rake:19 Tasks: TOP => mailserv:add_admin

Any idea ?

'gem env' give me : RubyGems Environment:   - RUBYGEMS VERSION: 1.8.10   - RUBY VERSION: 1.8.7 (2011-12-28 patchlevel 357) [i386-openbsd]   - INSTALLATION DIRECTORY: /usr/local/lib/ruby/gems/1.8   - RUBY EXECUTABLE: /usr/local/bin/ruby18   - EXECUTABLE DIRECTORY: /usr/local/bin   - RUBYGEMS PLATFORMS:     - ruby     - x86-unknown   - GEM PATHS:      - /usr/local/lib/ruby/gems/1.8      - /root/.gem/ruby/1.8   - GEM CONFIGURATION:      - :update_sources => true      - :verbose => true      - :benchmark => false      - :backtrace => false      - :bulk_threshold => 1000   - REMOTE SOURCES:      - http://rubygems.org/

'gem list rails' give me : rails (3.1.3, 2.3.4)

the file add_admin.rake : namespace :mailserv do   def ask_passwords     pass1 = ask("Password: ") do |q|       q.echo = "*"       q.validate = /^.{6,31}$/       q.responses[:not_valid] = "Please use a stronger password (min 6 characters)"     end     pass2 = ask("Password Confirm: ") {|q| q.echo = "*" }     while pass1 != pass2       say "\nPasswords don't match"       pass1 = ask("Password: ") do |q|         q.echo = "*"         q.validate = /^.{6,31}$/         q.responses[:not_valid] = "Please use a stronger password (min 6 characters)"       end       pass2 = ask("Password Confirm: ") {|q| q.echo = "*" }     end     return pass1 end   # Alias for add_admin   task :create_admin do     Rake::Task['mailserv:add_admin'].execute   end   desc "Create a new user."   task :add_admin => :environment do     require 'highline/import'     say "Add an Administrator to the system"     begin       begin         username = ask("username: ", String) do |q|           q.validate = /^([a-zA-Z0-9\_\-]+)$/           q.responses[:not_valid] = "Please use characters 'a-z, A-Z, 0-9, _-' only."         end         email = ask("E-mail (used to send status updates - not needed): ")         password = ask_passwords end while !agree("Is this correct? ", true)       admin = Admin.new(:username => username, :email => email,         :password => password)       unless admin.save         say "\n" + admin.errors.full_messages.join(", ") + "\n\n"       end     end while !admin.errors.size.zero?   end end

Thank you very much for your help.

i find the solution update Highline using : gem install highline