I have installed ruby on Windows 7 using the installer `Ruby 1.9.3-p125` which is the latest version (`ruby -v` shows the right version). Next, I downloaded `devkit-3.4.5r3-20091110`, which is also the latest version. When I tried the following in the installation directory,

```
ruby dk.rb init

```

the console showed an error:

```
ruby: No such file or directory -- dk.rb (LoadError)

```

I am new to ruby and I don't want to learn ruby — I just want to use [Jekyll](http://jekyllbootstrap.com/usage/jekyll-quick-start.html) which needs ruby. 

How can I fix this error?