The error says this:
Quote:Please try running this command again as root/Administrator.
I think you can solve the problem by doing what the error message said; running the command as root.
sudo npm install cordova -g
will request your password and run the command as root.
On Windows, you have to run the Command Prompt as administrator. Right-click on the file of the command prompt or on a shortcut to it, and select "Run as Administrator".