Enterprise and Small team Edition's are both supported on Windows 2012 servers and Windows 8. However, installers for v3 and v4 do not automatically configure the PIABWS web application in IIS v8. This will need to be done manually at the end of the normal PIAB install process.
To create the PIABWS web application manually you will need to follow these steps. NB the example I give allows you to use the DefaultappPool, you could create a new app pool with specific account - method is the same.
You will then need to add the default account for the web application to the PIAB database.
For more information please contact firstname.lastname@example.org