I have read all the questions for the same problems and I have tried everything but nothing is working for me when I try to add android platform for cordova.
I had the same issue with version 3.5.0.
The problem is, that the error message from the script check_reqs located in C:\Users\{yourUserName}\.cordova\lib\android\cordova\3.5.0\bin, is not forwarded correctly.
I run the mentioned script manually and got the following error message:
[Error: Please install Android target 19 (the Android newest SDK). Make sure you have the latest Android tools installed as well. Run "android" from your command-line to install/update any missing SDKs or tools.]
So basically to solve this issue you have to install the latest Android SDK.