You need this module for installing the Adaptive Theme. AT stands for Adaptive Theme. This theme has to be installed as a subtheme.
First install the theme. Do not activate it. (You don't see the theme in the list...) Than you install and activate the AT module.
In the theme configuration, a new tab appears. Click and give it a name.
Now you will find the Adaptive Theme in the list for activation. Look at the name.. (The theme itself has many possibilities.)