I am trying to install a gem like this:

C:\InstantRails\rails_apps\foodmarksthespot>ruby script/plugin install git://github.com/lazyatom/engines.git

Which returns this message:

Rails requires RubyGems >= 1.3.1 (you have 1.2.0). Please `gem update --system` and try again.

But when I try to update using:

gem update --system

it says:

Updating RubyGems
Nothing to update

This is on windows. How can I force it to upgrade the system to a specific version?

ruby-on-rails ruby rubygems
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