I installed cordova and create a new project.
But when I use this command to add android platform:
cordova platform add android
I had the same problem with the android@5.1.1 version. I solved this issue, checking what version of android is provided by cordova. You can check it in C:/Users/%USER%/.cordova/lib/npm-cache/cordova-android
Then, you install the android platform version provided. For me it was @5.1.0 which was in my cordova-android folder. So I used the cmd line following:
cordova platform add android@5.1.0 which should be a differnet version for you.
Kind regards !