I\'m trying to run a Junit Test case which i exported from Selenium IDE. Im getting above exception.I\'m using Windows XP,Firefox 20.0.1,and using selenium-server-standalone
Update to selenium-server-standalone-2.44.0.jar works for me (http://www.seleniumhq.org/download/).
It seems that you need a proper combination of browser, selenium-driver and selenium-server.
Ubuntu 14.04, Firefox 35.0.1 and selenium-webdriver 2.44.0 works for me in a Ruby on Rails app. Chrome didn't work since I updated it, even with the last released driver.