[INFO] found RubyInstaller v1.9.2 at C:/Ruby192C:/Ruby192/lib/ruby/1.9.1/win32/registry.rb:173:in `tr': invalid byte sequence in UTF-8 (ArgumentError) from C:/Ruby192/lib/ruby/1.9.1/win32/registry.rb:173:in `initialize' from C:/Ruby192/lib/ruby/1.9.1/win32/registry.rb:231:in `exception' from C:/Ruby192/lib/ruby/1.9.1/win32/registry.rb:231:in `raise' from C:/Ruby192/lib/ruby/1.9.1/win32/registry.rb:231:in `check' from C:/Ruby192/lib/ruby/1.9.1/win32/registry.rb:277:in `EnumKey' from C:/Ruby192/lib/ruby/1.9.1/win32/registry.rb:551:in `each_key' from D:/DevKit/dk.rb:119:in `block (2 levels) in scan_for' from C:/Ruby192/lib/ruby/1.9.1/win32/registry.rb:389:in `open' from C:/Ruby192/lib/ruby/1.9.1/win32/registry.rb:496:in `open' from D:/DevKit/dk.rb:118:in `block in scan_for' from D:/DevKit/dk.rb:116:in `each' from D:/DevKit/dk.rb:116:in `scan_for' from D:/DevKit/dk.rb:138:in `block in installed_rubies' from D:/DevKit/dk.rb:138:in `collect' from D:/DevKit/dk.rb:138:in `installed_rubies' from D:/DevKit/dk.rb:146:in `init' from D:/DevKit/dk.rb:313:in `run' from D:/DevKit/dk.rb:332:in `<main>'

devkit我安装过，楼主需注意要下载与本机ruby版本相同的devkit， 安装分三步
ruby dk.rb init
ruby dk.rb review
ruby dk.rb install

我遇到跟你一样的问题，解决了，发上方法来希望能帮到需要的人。我的Devkit安装在C盘，进入C:\DevKit\home\hm，打开.inputrc文件（用记事本或者别的vim等之类的编辑器），然后修改
set output-meta on
set convert-meta off
这两行（上面的是修改后的）。保存后再执行 ruby dk.rb init 就不会错了

解压devkit，提示不能打开怎么回事