Rails 'rake gems:install' error in windows

Sangmin Ryu wrote:

but Windows's result is fail.

That is result.
undefined method `collect' for nil:NilClass

I had the same problem and I discovered this blog post:

http://rails.lighthouseapp.com/projects/8994/tickets/462-loading-environment-fails-with-an-outdated-version-of-rubygems-while-using-config-gem-some_gem

Basically, I was running an old version of gem. Do a "gem update
--system"