WebDriver_in_Selenium.rb

I created a world object

module WebDriver
  @@browser = nil

  def self.extended(base)
    @@browser = Selenium::WebDriver.for :firefox if @@browser.nil?
  end
  
  at_exit do
    @@browser.quit
  end

  def browser
    @@browser
  end
end

the at_exit method is whining a little

/Library/Ruby/Gems/1.8/gems/selenium-webdriver-0.0.7/firefox/src/rb/lib/selenium/webdriver/firefox/extension_connection.rb:51:in `close': closed stream (IOError)
	from /Library/Ruby/Gems/1.8/gems/selenium-webdriver-0.0.7/firefox/src/rb/lib/selenium/webdriver/firefox/extension_connection.rb:51:in `quit'
	from /Library/Ruby/Gems/1.8/gems/selenium-webdriver-0.0.7/firefox/src/rb/lib/selenium/webdriver/firefox/bridge.rb:29:in `quit'
	from /Library/Ruby/Gems/1.8/gems/selenium-webdriver-0.0.7/common/src/rb/lib/selenium/webdriver/driver.rb:70:in `quit'
	from ./features/support/paths.rb:11