Android Studio: "Ok" button disabled in "Create new AVD" window

Issue

I downloaded and installed the latest Android Studio version which is 0.8.6 (beta) and I was stuck while trying to create a new Android Virtual Device.
I tried to follow these steps: https://developer.android.com/training/wearables/apps/creating.html but looks like the CPU/ABI is unavailable when I pick one of the types mentioned in that document (Android Wear Square/Round) and the skins named AndroidWearRound or AndroidWearSquare are also unavailble.
Here's a screenshot:

Solution

It's pretty likely that you forgot to download one of the system-images, either ARM EABI v7a or Intel x86. See the following screenshot:

Answered By - reVerse