Just in case someone is struggling with this, in my case I'm using Gradle 1.4 beta 1 and I NEED to keep it. So in order to make Android Studio works go to the terminal and run this:
launchctl setenv ANDROID_DAILY_OVERRIDE <your-value-on-error-message>
Restart Android Studio and the project will build again.
Kudos to UPDATE 2 here: https://emmanuelbernard.com/blog/2012/05/09/setting-global-variables-intellij/