unable to obtain stable firefox connection in 60 seconds (127.0.0.1:7055) (Selenium::WebDriver::Error::WebDriverError)
When I've received this error, it has been due to Firefox updating itself to a new version and Selenium WebDriver not having been updated to support this new version.
gem update selenium-webdriver
If you use Bundler, do:
bundle update selenium-webdriver
Still doesn't work? Check code.google.com with your firefox/selenium-webdriver version combination to see if there are any updates about it.
Meanwhile, you can get dev updates for the selenium-webdriver gem from:
Last resort: downgrade Firefox.