RubyGems error on update: undefined local variable or method `remote_gemspecs'

I updated rubygems:
>sudo gem update --system
        Password:
        Updating RubyGems
        Updating rubygems-update
        Successfully installed rubygems-update-1.3.1
        ERROR:  While executing gem ... (NameError)
            undefined local variable or method `remote_gemspecs' for
           #<gem ::Commands::UpdateCommand:0x14df818>
... but received this error:
undefined local variable or method `remote_gemspecs'
Reading the release notes prompted me to install the rubygems-update gem separately:
>sudo gem install rubygems-update
        Successfully installed rubygems-update-1.3.1
Finally, run the update_rubygems command to actually update:
>sudo update_rubygems
        Installing RubyGems 1.3.1
        mkdir -p /usr/local/lib/ruby/site_ruby/1.8
        mkdir -p /usr/local/bin
        install -c -m 0644 rbconfig/datadir.rb /usr/local/lib/ruby/site_ruby/1.8/rbconfig/datadir.rb
        .... more installation
        <br><br>
        &gt; gem -v
        1.3.1
Finally!

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