Problema com Rails no suse 10

quando tento fazer : rails teste ele gera o erro abaixo, o que pode ser e como resolver?

/opt/lib/ruby/gems/1.8/gems/activerecord-2.1.1/lib/active_record.rb:33: undefined method `gem' for main:Object (NoMethodError)

from /opt/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in `require__'

from /opt/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in `require'

from /opt/lib/ruby/site_ruby/1.8/rubygems.rb:182:in `activate'

from /opt/lib/ruby/site_ruby/1.8/rubygems.rb:181:in `each'

from /opt/lib/ruby/site_ruby/1.8/rubygems.rb:181:in `activate'

from /opt/lib/ruby/site_ruby/1.8/rubygems.rb:167:in `activate'

from /opt/lib/ruby/site_ruby/1.8/rubygems.rb:166:in `each'

from /opt/lib/ruby/site_ruby/1.8/rubygems.rb:166:in `activate'

from /opt/lib/ruby/site_ruby/1.8/rubygems.rb:37:in `require_gem_with_options'

from /opt/lib/ruby/site_ruby/1.8/rubygems.rb:31:in `require_gem'

from /opt/bin/rails:17