My windows had crashed, and, was reinstalling the software.
I was installing Android SDK API revision 12, and the JDK version that I was having on my system was JDK 7.
When I started the Android SDK installer, it said that, it was unable to find the JDK on my system.
I searched for the solution on the net, and, the simple solution for this (if you have a compatible JDK installed) is to just to press the BACK button and then press the NEXT, and you will see that, JDK is found.
This simple solution helped me solve my problem, I hope it helps to solve yours too.