bundle exec fails with "could not find rake-10.1.0 in any of the sources"

Question

I'm attempting to a deploy to a staging server using capistrano an existing application that seems to deploy fine to the production server. the staging server is a fresh build and i think it's a config issue, but I can't figure it out.

capistrano fails on assets:precompile try's to run

executing "cd -- /www/sites/{appname} /releases/20131009211055 && RAILS_ENV=production RAILS_GROUPS=assets bundle exec rake assets:precompile"

at which point it fails with the following:

[out :: {servername}] Could not find rake-10.1.0 in any of the sources

when I run the same command locally, i get the same error message as well. in fact, when i attempt to run any bundle exec command (e.g., bundle exec rails --version) i get the same error message.

my .bundle/config is as follows:

---
BUNDLE_FROZEN: '1'
BUNDLE_PATH: /www/sites/{appname?/shared/bundle
BUNDLE_WITHOUT: development:test
BUNDLE_DISABLE_SHARED_GEMS: '1'

I think it's a problem related to the gems not installing to the bundle path. looking into the BUNDLE_PATH/ruby/1.9.1 and the folder is empty

I've tried Bundle Install and it says it's using all the gems from my Gemfile and installing to BUNDLE_PATH, but they don't appear.

my Gemfile is as follows:

source 'https://rubygems.org'

gem 'rails', '3.2.11'
gem 'rake', '10.1.0'
gem 'mysql2'
gem 'devise'

# Gems used only for assets and not required
# in production environments by default.
group :assets do
  gem 'sass-rails',   '~> 3.2.3'
  gem 'coffee-rails', '~> 3.2.1'

  # See https://github.com/sstephenson/execjs#readme for more supported runtimes
  gem 'therubyracer', :platforms => :ruby

  gem 'uglifier', '>= 1.0.3'
end

gem 'jquery-rails'
gem 'jquery-ui-rails'
gem "paperclip"
gem "rmagick"
gem 'omniauth'
gem 'omniauth-facebook'
gem 'omniauth-google-oauth2'
gem 'oauth2'
gem 'koala'
gem 'httparty'
gem "carrierwave"
gem 'activeadmin'
gem "activeadmin-settings"
gem 'mini_magick'
gem 'rabl'
gem 'rest-open-uri'
gem 'apipie-rails'
gem "capistrano", :group => :development

Other relevant info from gem environment:

RubyGems Environment:
  - RUBYGEMS VERSION: 2.1.4
  - RUBY VERSION: 1.9.3 (2013-06-27 patchlevel 448) [x86_64-linux]
  - INSTALLATION DIRECTORY: /usr/local/rvm/gems/ruby-1.9.3-p448
  - RUBY EXECUTABLE: /usr/local/rvm/rubies/ruby-1.9.3-p448/bin/ruby
  - EXECUTABLE DIRECTORY: /usr/local/rvm/gems/ruby-1.9.3-p448/bin
  - SPEC CACHE DIRECTORY: /home/ec2-user/.gem/specs
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86_64-linux
  - GEM PATHS:
     - /usr/local/rvm/gems/ruby-1.9.3-p448
     - /usr/local/rvm/gems/ruby-1.9.3-p448@global
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :backtrace => false
 - :bulk_threshold => 1000
  - REMOTE SOURCES:
     - https://rubygems.org/
  - SHELL PATH:
     - /usr/local/rvm/gems/ruby-1.9.3-p448/bin
     - /usr/local/rvm/gems/ruby-1.9.3-p448@global/bin
     - /usr/local/rvm/rubies/ruby-1.9.3-p448/bin
     - /usr/local/rvm/bin
     - /usr/local/bin
     - /bin
     - /usr/bin
     - /usr/local/sbin
     - /usr/sbin
     - /sbin
     - /opt/aws/bin
     - /home/ec2-user/bin

At this point I'm at a loss on what to investigate. Any ideas on what's wrong?