Rails: Why "sudo" command is not recognized?

Sudo is a Unix specific command designed to allow a user to carry out administrative tasks with the appropriate permissions.

Windows does not have (need?) this.

Run the command with the sudo removed from the start.

sudo is a Unix/Linux command. It's not available in Windows.

That you are running Windows. Read:

http://en.wikipedia.org/wiki/Sudo

It basically allows you to execute an application with elevated privileges. If you want to achieve a similar effect under Windows, open an administrative prompt and execute your command from there. Under Vista, this is easily done by opening the shortcut while holding Ctrl+Shift at the same time.

That being said, it might very well be possible that your account already has sufficient privileges, depending on how your OS is setup, and the Windows version used.