Ah, well in my case it was an issue with cordova 3.3. It was fixed when I upgraded to 3.4 so I’m not sure what the issue was. Best thing I can suggest right now is it
uninstall both cordova and the ionic cli
install them again
make a new project
try to add the plugin again
If that works then great! If not we may have a bigger issue. Let me know how it goes