Rails installation fails in netbeans 6.9.1 IDE, in Ubuntu?

I,m getting the开发者_如何学JAVA following error:-

ERROR: Error installing rails:

i18n requires RubyGems version >= 1.3.6

These the gems and ruby version installed in my system.

:~$ ruby -v

ruby 1.8.7 (2010-08-16 patchlevel 302) [i686-linux]

:~$ gem -v

1.3.7

:~$ rails -v

Rails 3.0.1

:~$

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maybe http://wiki.netbeans.org/RubyGemsNB6Ubuntu will be of assistance.