Problem:

Is Windows Server 2012 supported by ACUCOBOL-GT runtime?

Resolution:

Version 9.1.2.1 can be run with no issue on Windows Server 2012.
Anyway, the first certified release will be 9.2.0, available in next spring 2013. 

It is very important to use 9.1.2.1 on this new platform since earlier releases of runtime may have some issues with calls to system functionalities (CALL SYSTEM, CALL C$SYSTEM).