fix for Invalid gemspec in [...../.gemspec]: Illformed requirement

command_to_fix_the_gems.txt

# restore the gems that raised "Illformed requirement"
$ gem pristine selenium-webdriver
$ gem pristine cucumber
$ gem pristine multi_xml
$ gem pristine mogli
$ gem pristine httparty
$ gem pristine simplecov-html
$ gem pristine simplecov

result_of_bundle_update.txt

Fetching source index for http://rubygems.org/

...

Using json_pure (1.6.0) 
Using rubyzip (0.9.4) 
Installing selenium-webdriver (2.6.0) Invalid gemspec in [/usr/local/rvm/gems/ruby-1.9.2-p290/specifications/cucumber-1.0.5.gemspec]: Illformed requirement ["#<Syck::DefaultKey:0x9c65328> 0.8.4"]
Using xpath (0.1.4) 
Using capybara (1.0.1) 

...

Using gherkin (2.4.18) 
Using term-ansicolor (1.0.6) 
Installing cucumber (1.0.6) Invalid gemspec in [/usr/local/rvm/gems/ruby-1.9.2-p290/specifications/cucumber-1.0.5.gemspec]: Illformed requirement ["#<Syck::DefaultKey:0x9c65328> 0.8.4"]
Using cucumber-rails (1.0.2) 
Using daemons (1.1.4) 
Using database_cleaner (0.6.7) 
Using delayed_job (2.1.4) 
Using hashie (1.1.0) 
Using multi_json (1.0.3) 
Installing multi_xml (0.4.0) Invalid gemspec in [/usr/local/rvm/gems/ruby-1.9.2-p290/specifications/cucumber-1.0.5.gemspec]: Illformed requirement ["#<Syck::DefaultKey:0x9c65328> 0.8.4"]
Installing httparty (0.8.0) Invalid gemspec in [/usr/local/rvm/gems/ruby-1.9.2-p290/specifications/cucumber-1.0.5.gemspec]: Illformed requirement ["#<Syck::DefaultKey:0x9c65328> 0.8.4"]
Using mogli (0.0.31) from git://github.com/mieple/mogli.git (at master) Invalid gemspec in [/usr/local/rvm/gems/ruby-1.9.2-p290/specifications/cucumber-1.0.5.gemspec]: Illformed requirement ["#<Syck::DefaultKey:0x9c65328> 0.8.4"]
Using ruby-hmac (0.4.0) 
Using facebooker2 (0.0.11) from git://github.com/mieple/facebooker2.git (at master) 

...

Using ruby-debug19 (0.11.6) 
Using ruby-prof (0.10.8) 
Installing simplecov-html (0.5.3) Invalid gemspec in [/usr/local/rvm/gems/ruby-1.9.2-p290/specifications/cucumber-1.0.5.gemspec]: Illformed requirement ["#<Syck::DefaultKey:0x9c65328> 0.8.4"]
Installing simplecov (0.5.3) Invalid gemspec in [/usr/local/rvm/gems/ruby-1.9.2-p290/specifications/cucumber-1.0.5.gemspec]: Illformed requirement ["#<Syck::DefaultKey:0x9c65328> 0.8.4"]
Using simplecov-rcov (0.2.3) 
Using split (0.2.4) 
Using spork (0.8.5) 
Using watchr (0.7) 
Using whenever (0.7.0) 
Your bundle is updated! Use `bundle show [gemname]` to see where a bundled gem is installed.

This didn't work for me.

However:

gem update --system
worked for me to rubygems fix #256