Updated to Rails 3.0.0.beta4. Is it the problem?

I have updated to Rails 3.0.0.beta4

I’m trying to install this plugin:

There is a command I’m trying to run: rails generate devise:install

But, I get the following: http://pastie.org/1050651

For example, in Rails 2.3.8, when I used to create a new Rails
application I used to type:

Rails app_name

But, I noticed that with Rails 3.0.0.beta4, I had to do that using:

Rails new app_name

So, how can I run: rails generate devise:install ?