Running with Ruby 1.9.2
The IDE complains that The gem ruby-debug-base19x is required and offers to install it.
However, upon attempting to install it it displays the message
Failed to install gems. Following gems were not installed: C:/Program Files (x86)/JetBrains/RubyMine 3.2.4/rb/gems/ruby-debug-base19x-0.11.30.pre2.gem: Error installing ruby-debug-base19x-0.11.30.pre2.gem: The 'linecache19' 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' C:/Program Files (x86)/JetBrains/RubyMine 3.2.4/rb/gems/ruby-debug-ide-0.4.17.beta8.gem: Error installing ruby-debug-ide-0.4.17.beta8.gem: The 'ruby-debug-ide' 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' linecache19 (0.5.12): Error installing linecache19: The 'linecache19' 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'
I followed its advice to download the DevKit - but the DevKit upon attempting to install, said that it was already correctly installed as part of Ruby.
Any advice?
The problem is not specific to RubyMine, I'd try to reinstall Ruby and DevKit from scratch. Verify that DevKit actually works using a test from the installation guide:
gem install rdiscount --platform=ruby
ruby -rubygems -e "require 'rdiscount'; puts RDiscount.new('**Hello RubyInstaller**').to_html"
If it works fine, try to install the debug gems manually from the console using the following commands:
gem install ruby-debug-base19x --pre
gem install ruby-debug-ide --pre
Post logs, provide more details if it still doesn't work for you.