There are a couple of technologies and methodologies that we follow.
The version of rails is >=3.1.0
I removed Steak and ran the examples. It doesn't find the alias 'feature', so I think that DSL is not yet integrated, perhaps?
I think until capybara 1.0 is ready you need to get it from git:Anyway, it's only a suggestion (I'm a BDD newbie) so maybe it's not necessary to live so much on the edge :)
gem 'capybara', :git => 'git://github.com/jnicklas/capybara.git'