Cucumber + Capybara + tiny_mce Problem

Hello
I want to test the the tiny_mce using cucumber and capybara and I got a
solution in the following thred "
http://groups.google.com/group/ruby-capybara/browse_thread/thread/711d08ddceb9276?pli=1"
but somehow I am getting the following error

private method `bridge’ called for
#<Selenium::WebDriver::Driver:0x…fb55cd4f0 browser=:firefox>
(NoMethodError)

Is there anyone who faced the same issue and able to resolve it please
share
your solution

Thanks
Abhis