terminal error

imac:~ Vivid$ rails -v
/Library/Ruby/Site/1.8/rubygems/dependency.rb:247:in `to_specs': Could not find railties (>= 0) amongst [bundler-1.2.3, rake-10.0.3, rubygems-bundler-1.1.0, rvm-1.11.3.5] (Gem::LoadError)
	from /Library/Ruby/Site/1.8/rubygems/dependency.rb:256:in `to_spec'
	from /Library/Ruby/Site/1.8/rubygems.rb:1231:in `gem'
	from /usr/bin/rails:22