Unable to add plugins. Perhaps your version of Cordova is too old

http://forum.ionicframework.com/t/unable-to-add-plugins-perhaps-your-version-of-cordova-is-too-old/3807/10

Just to add to this, had a similar problem on a Windows 8.1 box running latest version of npm and cordova. My problem was related to the Ionic Keyboard plugin trying to download to a directory that does not exist... rather than anything to do with cordova being out of date. As soon as I added that directory tree in my AppData directory it worked fine.