I’m having problems installing json or rmagick gems on Windows, which I need because I am trying to install Redmine 2.1.4.
As none of the procedures worked out-of-the-box for me and have struggled with it myself for a couple of hours, I thought I’d just ask here for help.
I’m assuming you don’t have Ruby installed yet. If you do, as any of other components mentioned below, probably it’s the wisest to uninstall them before proceeding with installation.
This tutorial should help you avoid problems with
jsonandrmagickgems on Windows.First, download Redmine 2.1.4 from rubyforge as zip or from SVN or Git as described on the relevant Redmine Wiki page. rubyforge tends not to work, so you can be forced to use the latter.
Download RubyInstaller (1.9.3 at the time of this writing) and DevelopmentKit from rubyinstaller.org
Install Ruby using the downloaded installer. Use a directory without spaces in name, i.e. don’t install it to Program Files. I checked the options as below

Open command line, check if Ruby path has been added to your system.
ruby --versionshould show the version installed, 1.9.3 in my case. If you had command line opened while installing Ruby, close and reopen it to load path.Extract DevKit to a path with no spaces. Change to DevKit’s directory (might be e.g. under Ruby’s installation, i.e. C:\Ruby193\DevKit). Execute the following:
ruby dk.rb initruby dk.rb review(should detect Ruby’s installation path correctly)ruby dk.rb installInstall bundler gem
gem install bundlerGo to Redmine home directory. Execute
bundle install. You will probably (if not yet fixed) get thermagickerror – don’t worry yet.Go get ImageMagick. I picked

ImageMagick-6.8.0-7-Q16-windows-dll.exe. Install to a directory whose path doesn’t include spaces, e.g.C:\ImageMagick. Choose to install header files as well, as below:Add
ImageMagickhome topath. Close command line and reopen it. This will reload path.Execute `gem install rmagick –platform=ruby — –with-opt-lib=c:/ImageMagick/lib –with-opt-include=c:/ImageMagick/include
Go to Redmine home directory again. Execute
bundle installagain. Should work now.Hope that helps!