Error when run gem install bundler

Question

I'm trying to install bundler but I'm getting the following:

/Library/Ruby/Site/1.8/rubygems/config_file.rb:39: uninitialized constant Gem::UserInteraction (NameError)
from /Library/Ruby/Site/1.8/rubygems/core_ext/kernel_require.rb:55:in `gem_original_require'
from /Library/Ruby/Site/1.8/rubygems/core_ext/kernel_require.rb:55:in `require'
from /Library/Ruby/Site/1.8/rubygems/specification.rb:1430:in `build_extensions'
from /Library/Ruby/Site/1.8/rubygems/stub_specification.rb:60:in `build_extensions'
from /Library/Ruby/Site/1.8/rubygems/basic_specification.rb:56:in `contains_requirable_file?'
from /Library/Ruby/Site/1.8/rubygems/specification.rb:925:in `find_inactive_by_path'
from /Library/Ruby/Site/1.8/rubygems/specification.rb:1031:in `find'
from /Library/Ruby/Site/1.8/rubygems/specification.rb:924:in `each'
from /Library/Ruby/Site/1.8/rubygems/specification.rb:924:in `find'
from /Library/Ruby/Site/1.8/rubygems/specification.rb:924:in `find_inactive_by_path'
from /Library/Ruby/Site/1.8/rubygems.rb:185:in `try_activate'
from /Library/Ruby/Site/1.8/rubygems/core_ext/kernel_require.rb:132:in `require'
from /Library/Ruby/Site/1.8/rubygems/user_interaction.rb:8
from /Library/Ruby/Site/1.8/rubygems/core_ext/kernel_require.rb:55:in `gem_original_require'
from /Library/Ruby/Site/1.8/rubygems/core_ext/kernel_require.rb:55:in `require'
from /Library/Ruby/Site/1.8/rubygems/command.rb:9
from /Library/Ruby/Site/1.8/rubygems/core_ext/kernel_require.rb:55:in `gem_original_require'
from /Library/Ruby/Site/1.8/rubygems/core_ext/kernel_require.rb:55:in `require'
from /Library/Ruby/Site/1.8/rubygems/command_manager.rb:7
from /Library/Ruby/Site/1.8/rubygems/core_ext/kernel_require.rb:55:in `gem_original_require'
from /Library/Ruby/Site/1.8/rubygems/core_ext/kernel_require.rb:55:in `require'
from /Library/Ruby/Site/1.8/rubygems/gem_runner.rb:8
from /Library/Ruby/Site/1.8/rubygems/core_ext/kernel_require.rb:55:in `gem_original_require'
from /Library/Ruby/Site/1.8/rubygems/core_ext/kernel_require.rb:55:in `require'
from /usr/bin/gem:9

Down anybody knows how can I fix?

Thank you!

Edit: formatting

Answer 1

It looks like you're having a similar problem to this guy, the solution being just simply going to https://rubygems.org/pages/download and downloading it manually until the problem is fixed.