Production Rake Tasks Don't Recognize My Models - ruby-on-rails

Question

When I was running Heroku Bamboo, this was never a problem. Now, on Cedar, I get errors whenever I try to access my models from within a rake task on the server. This happens with rake db:seed, a standard rake task, as well as my own custom built tasks that explicitly include :environment. I even do so redundantly:
namespace :db do
desc "Update db"
task :new_seed => :environment do
require './Scraped_Data/Games/code/column-headers.rb'
require 'csv'
require 'net/http'
require './config/environment.rb'
# code here...
end
end
I can't find any mention of this issue elsewhere, and all of these tasks run perfectly in development. Thanks for any insights, and here is the full error message rake tasks spit out as soon as they encounter a model of mine on Heroku:
rake aborted!
uninitialized constant Object::Movie
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/ext/module.rb:36:in `const_missing'
/app/lib/tasks/new_seed.rake:187:in `block in load_scraped_data'
/app/vendor/bundle/ruby/1.9.1/gems/rest-open-uri-1.0.0/lib/rest-open-uri.rb:37:in `open'
/app/vendor/bundle/ruby/1.9.1/gems/rest-open-uri-1.0.0/lib/rest-open-uri.rb:37:in `open'
/app/lib/tasks/new_seed.rake:148:in `load_scraped_data'
/app/lib/tasks/new_seed.rake:550:in `block (2 levels) in <top (required)>'
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `call'
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `block in execute'
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `each'
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `execute'
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain'
/usr/local/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:144:in `invoke'
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:116:in `invoke_task'
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block (2 levels) in top_level'
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `each'
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block in top_level'
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:88:in `top_level'
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:66:in `block in run'
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run'
/app/vendor/bundle/ruby/1.9.1/gems/rake-0.9.2.2/bin/rake:33:in `<top (required)>'
/app/vendor/bundle/ruby/1.9.1/bin/rake:19:in `load'
/app/vendor/bundle/ruby/1.9.1/bin/rake:19:in `<main>'
Tasks: TOP => db:new_seed

Answer 1

By default threadsafe set dependency_loading = false
If you want to enable threadsafe in your application and access to your models in your task, you'll need to load it.
# Enable threaded mode
config.threadsafe!
config.dependency_loading = true if $rails_rake_task
Ref.: http://nowhereman.github.com/how-to/rails_thread_safe/
Hope this help!

Answer 2

I had threadsafe! = true configured in my production environment at config/environments/production.rb
Disabling this solves the problem.
The answer found here: rake aborted! uninitialized constant Object::Country, why can't see model? gives some more explanation and other workaround options (particularly the last link)