Error thrown via 'rake ts:conf'

array_total.rb

class Array
  def total(attr_name)
    collect(&attr_name).compact.sum
  end
end

error.sh

cameron@cam-debian:~/projects/chc/chapp(rbx)$ rake ts:conf --trace
(in /home/cameron/projects/chc/chapp)
DEPRECATION WARNING: Rake tasks in vendor/plugins/asset_packager/tasks, vendor/plugins/exception_logger/tasks, vendor/plugins/mapit/tasks, vendor/plugins/seed-fu/tasks, and vendor/plugins/state_machine/tasks are deprecated. Use lib/tasks instead. (called from __script__ at /home/cameron/.rvm/gems/rbx-master@chapp/gems/rails-2.3.14/lib/tasks/rails.rb:10)
** Invoke ts:conf (first_time)
** Invoke thinking_sphinx:configure (first_time)
** Invoke thinking_sphinx:app_env (first_time)
** Execute thinking_sphinx:app_env
** Invoke environment (first_time)
** Execute environment
rake aborted!
method 'total': given 0, expected 1
kernel/common/array.rb:1914:in `recursively_flatten'
kernel/common/thread.rb:50:in `detect_recursion'
kernel/common/array.rb:1912:in `recursively_flatten'
kernel/common/array.rb:909:in `flatten'
/home/cameron/.rvm/gems/rbx-master@chapp/gems/activesupport-2.3.14/lib/active_support/dependencies.rb:551:in `new_constants_in'
/home/cameron/.rvm/gems/rbx-master@chapp/gems/activesupport-2.3.14/lib/active_support/dependencies.rb:182:in `require'
/home/cameron/.rvm/gems/rbx-master@chapp/gems/rails-2.3.14/lib/tasks/misc.rake:4:in `__script__'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:636:in `execute'
kernel/bootstrap/array.rb:76:in `each'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:631:in `execute'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:597:in `invoke_with_call_chain'
/home/cameron/.rvm/rubies/rbx-master/lib/monitor.rb:191:in `synchronize (mon_synchronize)'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:583:in `invoke'
/home/cameron/.rvm/gems/rbx-master@chapp/gems/thinking-sphinx-1.4.1/lib/thinking_sphinx/tasks.rb:7:in `__script__'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:636:in `execute'
kernel/bootstrap/array.rb:76:in `each'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:631:in `execute'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:597:in `invoke_with_call_chain'
/home/cameron/.rvm/rubies/rbx-master/lib/monitor.rb:191:in `synchronize (mon_synchronize)'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:607:in `invoke_prerequisites'
kernel/bootstrap/array.rb:76:in `each'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:604:in `invoke_prerequisites'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:596:in `invoke_with_call_chain'
/home/cameron/.rvm/rubies/rbx-master/lib/monitor.rb:191:in `synchronize (mon_synchronize)'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:607:in `invoke_prerequisites'
kernel/bootstrap/array.rb:76:in `each'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:604:in `invoke_prerequisites'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:596:in `invoke_with_call_chain'
/home/cameron/.rvm/rubies/rbx-master/lib/monitor.rb:191:in `synchronize (mon_synchronize)'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:583:in `invoke'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:2051:in `invoke_task'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
kernel/bootstrap/array.rb:76:in `each'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:2001:in `run'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/lib/rake.rb:1998:in `run'
/home/cameron/.rvm/gems/rbx-master@global/gems/rake-0.8.7/bin/rake:31:in `__script__'
kernel/common/kernel.rb:732:in `load'
/home/cameron/.rvm/gems/rbx-master@global/bin/rake:19:in `__script__'
kernel/delta/codeloader.rb:65:in `load_script'
kernel/delta/codeloader.rb:90:in `load_script'
kernel/loader.rb:618:in `script'
kernel/loader.rb:769:in `main'