You can open Terminal and type "which rails" and "which rake" to see the correct paths.
Vish
Not really, I don't use Radrails. But the rake tasks for a project are within the rails-1.1.x gem directory, usually: /usr/local/lib/ruby/gems/1.8/gems/rails-1.1.x/lib/tasks. If you have to type that into Radrails tho, it's dumber than I thought it was. So you're probably doing something wrong.
Vish