I am using the ADT bundle (build v22.3) on Mac.
I followed the screenshot below to create a new activity:
from this guide: http://developer.android.com/training/basics/firstapp/starting-activity.html
However, once I press “Finish” no activity is created. There isn't even a sign of the activity in the manifest or R.java files.
I had the same problem. First wipe(remove) all the things about ADT and Eclipes. Then again start to configure/install ADT bundle and Eclipes step by step. And I think it's better try to find different Eclipes version and do it.(Different Eclipes version only).
After installed Eclipes and related tools, install Android SDK platform with one android version for check whether the problem was solved or not. I used Android 2.3.3 (Gingerbread).
It worked for me. And hope it will solve your matter too. :D