Installing plugin yields error

I am trying to install the plugin using ruby 1.9.2 and rails 3.0.9, when I run the following command to install

```
rails plugin install git://github.com/sandipransing/rails_tiny_mce.git
```

it errors with this

```
/railties-3.0.9/lib/rails/commands/plugin.rb:277:in `<top (required)>': Commands is not a module (TypeError)
```

Is there something I'm doing wrong?
