Could not find gem 'factory_girl_rails when upgrading redmine

i have recently upgraded bitnami redmine stack from 1.4.1-0 to 2.0.3-1. everything goes fine until i try to migrate my plugins:-

C:\Program Files\BitNami Redmine Stack 2.0.3-1\apps\redmine\htdocs>rake redmine:plugins:migrate RAILS_ENV=production

←[31mCould not find gem 'factory_girl_rails (>= 0) x86-mingw32' in any of the gem sources listed in your Gemfile.←[0m←[33mRun bundle install to install missing gems.←[0m

i then ran the 'bundle install', which seemed to run ok:-

Fetching source index for http://rubygems.org/
Fetching source index for http://rubygems.org/
Using rake (0.9.2.2)
Using i18n (0.6.0)
Using multi_json (1.1.0)
Using activesupport (3.2.6)
Using builder (3.0.0)
Using activemodel (3.2.6)
Using erubis (2.7.0)
Using journey (1.0.3)
Using rack (1.4.1)
Using rack-cache (1.2)
Using rack-test (0.6.1)
Using hike (1.2.1)
Using tilt (1.3.3)
Using sprockets (2.1.3)
Using actionpack (3.2.6)
Using mime-types (1.18)
Using polyglot (0.3.3)
Using treetop (1.4.10)
Using mail (2.4.4)
Using actionmailer (3.2.6)
Using arel (3.0.2)
Using tzinfo (0.3.33)
Using activerecord (3.2.6)
Using activeresource (3.2.6)
Using bundler (1.0.21)
Using coderay (1.0.6)
Using daemons (1.0.10)
Using eventmachine (0.12.10)
Using fastercsv (1.5.4)
Using json (1.4.6)
Using mysql (2.8.1)
Using net-ldap (0.3.1)
Using rack-ssl (1.3.2)
Using rdoc (3.11)
Using thor (0.14.6)
Using railties (3.2.6)
Using rails (3.2.6)
Using prototype-rails (3.2.1)
Using ruby-openid (2.1.8)
Using rack-openid (1.3.1)
Using rmagick (2.12.0)
Using thin (1.3.1)
Your bundle is complete! Use bundle show [gemname] to see where a bundled gemis installed.

until i tried to run the migration again, and got this:-

rake aborted!
Please install the mysql2 adapter: gem install activerecord-mysql2-adapter (mysql2 is not part of the bundle. Add it to Gemfile.)

Tasks: TOP => redmine:plugins:migrate => environment (See full trace by running task with --trace)

i attempted to therefore install that, but failed:-

C:\Program Files\BitNami Redmine Stack 2.0.3-1\apps\redmine\htdocs>gem install activerecord-mysql2-adapter
ERROR: Could not find a valid gem 'activerecord-mysql2-adapter' (>= 0) in any repository
ERROR: Possible alternatives: activerecord-jdbcmysql-adapter, activerecord-jdbch2-adapter, activerecord-odbc-adapter, activerecord-jdbcmssql-adapter, activerecord-postgis-adapter

i then done abit of googling. someone suggested deleting my Rakefile.lock file, and run the 'bundle install' again, i did this, and got this:-

Fetching source index for http://rubygems.org/
Fetching source index for http://rubygems.org/
Using rake (0.9.2.2)
Using i18n (0.6.0)
Installing multi_json (1.3.6)
Using activesupport (3.2.6)
Using builder (3.0.0)
Using activemodel (3.2.6)
Using erubis (2.7.0)
Installing journey (1.0.4)
Using rack (1.4.1)
Using rack-cache (1.2)
Using rack-test (0.6.1)
Using hike (1.2.1)
Using tilt (1.3.3)
Using sprockets (2.1.3)
Using actionpack (3.2.6)
Installing mime-types (1.19)
Using polyglot (0.3.3)
Using treetop (1.4.10)
Using mail (2.4.4)
Using actionmailer (3.2.6)
Using arel (3.0.2)
Using tzinfo (0.3.33)
Using activerecord (3.2.6)
Using activeresource (3.2.6)
Using bundler (1.0.21)
Installing coderay (1.0.7)
Installing daemons (1.1.8)
Using eventmachine (0.12.10)
Installing fastercsv (1.5.5)
Installing json (1.7.3)
Gem::InstallError: The 'json' native gem requires installed build tools.

Please update your PATH to include build tools or download the DevKit
from 'http://rubyinstaller.org/downloads' and follow the instructions
at 'http://github.com/oneclick/rubyinstaller/wiki/Development-Kit'
An error occured while installing json (1.7.3), and Bundler cannot continue.
Make sure that gem install json -v '1.7.3' succeeds before bundling.

Does anyone have any idea's? i didn't want to proceeed any further, as i had probbaly broken it enough! luckily it is a virtual machine, so i have restored back back to my start point, so the same problem will happen again, when i try to upgrade. any siggestions would be appreciated.