When I try to install ZenTest:

gem install ZenTest

I get the following error:

Invalid gemspec in [C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/specifications/ZenTest-4.8.4.gemspec]: Illformed requirement ["< 2.1, >= 1.8"]

I tried cleaning up the gems and removing the ZenTest to no avail.

What's wrong?

ruby-on-rails rubygems zentest
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