Rvm: Ruby를 제거할 수 없습니다. 실행할 수 없기 때문에 특정 버전을 다시 설치하고 싶습니다. 앱을 테스트하고 오류가 발생했습니다.

ruby 2.1.0을 사용하여 ruby를 제거하거나, ruby를 다시 설치하거나, ​​특정 rails 프로젝트를 시작 또는 테스트할 수 없습니다.
새 루비를 제거하고 설치하는 방법은 무엇입니까?

오류의 예:
1.

$ rails s
/Users/user/.rvm/gems/ruby-2.1.0/bin/rails:23:in `load': cannot load such file -- /Users/user/.rvm/gems/ruby-2.1.0/gems/railties-4.1.1/bin/rails (LoadError)
    from /Users/user/.rvm/gems/ruby-2.1.0/bin/rails:23:in `<main>'
    from /Users/user/.rvm/gems/ruby-2.1.0/bin/ruby_executable_hooks:15:in `eval'
    from /Users/user/.rvm/gems/ruby-2.1.0/bin/ruby_executable_hooks:15:in `<main>'

2.

$ rvm remove ruby-2.1.0
ruby-2.1.0 - #removing src/ruby-2.1.0..
ruby-2.1.0 - #removing rubies/ruby-2.1.0......................................
Error running '__rvm_rm_rf /Users/user/.rvm/rubies/ruby-2.1.0',
showing last 15 lines of /Users/user/.rvm/log/1405545940_ruby-2.1.0/remove.rubies.log
rm: /Users/user/.rvm/rubies/ruby-2.1.0/lib/ruby/gems/2.1.0/gems/nokogiri-1.6.2.1/test: Permission denied
rm: /Users/user/.rvm/rubies/ruby-2.1.0/lib/ruby/gems/2.1.0/gems/nokogiri-1.6.2.1/test_all: Permission denied
rm: /Users/user/.rvm/rubies/ruby-2.1.0/lib/ruby/gems/2.1.0/gems/nokogiri-1.6.2.1/Y_U_NO_GEMSPEC.md: Permission denied
rm: /Users/user/.rvm/rubies/ruby-2.1.0/lib/ruby/gems/2.1.0/gems/nokogiri-1.6.2.1: Directory not empty
rm: /Users/user/.rvm/rubies/ruby-2.1.0/lib/ruby/gems/2.1.0/gems: Directory not empty
rm: /Users/user/.rvm/rubies/ruby-2.1.0/lib/ruby/gems/2.1.0: Directory not empty
rm: /Users/user/.rvm/rubies/ruby-2.1.0/lib/ruby/gems: Directory not empty
rm: /Users/user/.rvm/rubies/ruby-2.1.0/lib/ruby: Directory not empty
rm: /Users/user/.rvm/rubies/ruby-2.1.0/lib: Directory not empty
rm: /Users/user/.rvm/rubies/ruby-2.1.0: Directory not empty
++ typeset ret=1
++ rvm_debug '__rvm_rm_rf error removing target dir '\''/Users/user/.rvm/rubies/ruby-2.1.0'\''.'
++ ((  0  ))
++ return 0
++ return 1

nokogiri를 제거하면 다른 보석에 영향을 미칩니다.

수정을 위한 다른 시도:
Unknown ruby string (do not know how to handle): ruby-2.1.0.