Ios – Cocoapods: LoadError – no such file to load

I am trying to add a pod to my Xcode project. I am getting this error:

LoadError – no such file to load — xcodeproj/prebuilt/universal-darwin13.0-1.8.7/xcodeproj_ext
/Library/Ruby/Site/1.8/rubygems/core_ext/kernel_require.rb:55:in gem_original_require' /Library/Ruby/Site/1.8/rubygems/core_ext/kernel_require.rb:55:in require'
/Library/Ruby/Gems/1.8/gems/xcodeproj-0.14.0/lib/xcodeproj/ext.rb:6
/Library/Ruby/Site/1.8/rubygems/core_ext/kernel_require.rb:55:in gem_original_require' /Library/Ruby/Site/1.8/rubygems/core_ext/kernel_require.rb:55:in require'
/Library/Ruby/Gems/1.8/gems/xcodeproj-0.14.0/lib/xcodeproj/project.rb:4
/Library/Ruby/Gems/1.8/gems/cocoapods-0.27.1/lib/cocoapods/installer/analyzer.rb:488:in compute_target_platforms' /Library/Ruby/Gems/1.8/gems/cocoapods-0.27.1/lib/cocoapods/installer/analyzer.rb:485:in each'
/Library/Ruby/Gems/1.8/gems/cocoapods-0.27.1/lib/cocoapods/installer/analyzer.rb:485:in compute_target_platforms' /Library/Ruby/Gems/1.8/gems/cocoapods-0.27.1/lib/cocoapods/installer/analyzer.rb:55:in analyze'
/Library/Ruby/Gems/1.8/gems/cocoapods-0.27.1/lib/cocoapods/installer.rb:171:in analyze' /Library/Ruby/Gems/1.8/gems/cocoapods-0.27.1/lib/cocoapods/installer.rb:94:in resolve_dependencies'
/Library/Ruby/Gems/1.8/gems/cocoapods-0.27.1/lib/cocoapods/user_interface.rb:52:in section' /Library/Ruby/Gems/1.8/gems/cocoapods-0.27.1/lib/cocoapods/installer.rb:93:in resolve_dependencies'
/Library/Ruby/Gems/1.8/gems/cocoapods-0.27.1/lib/cocoapods/installer.rb:86:in install!' /Library/Ruby/Gems/1.8/gems/cocoapods-0.27.1/lib/cocoapods/command/project.rb:38:in run_install_with_update'
/Library/Ruby/Gems/1.8/gems/cocoapods-0.27.1/lib/cocoapods/command/project.rb:68:in run' /Library/Ruby/Gems/1.8/gems/claide-0.3.2/lib/claide/command.rb:206:in run'
/Library/Ruby/Gems/1.8/gems/cocoapods-0.27.1/lib/cocoapods/command.rb:51:in run' /Library/Ruby/Gems/1.8/gems/cocoapods-0.27.1/bin/pod:19 /usr/bin/pod:23:in load'
/usr/bin/pod:23

My podfile contents:

pod 'RestKit', '~> 0.21.0'

Any help would be appreciated!