Hi BWW,
As Philippe said, version 7.6 will be out soon and will include support for Windows 8 and Windows 2012. We don't have the exact release date, however, so for now, we must be patient, and wait till 7.6 is released.
If you REALLY need to install PlanetPress on the 2012 server right now, feel free to try it. Most of the functionalities actually works fine, the only thing I've seen that's not working is the HTTP Server Input. I personally have it installed on Windows 8, and so far, almost everything works just fine, besides HTTP Server Input. So if your processes don't use that, feel free to try the current version. Just remember that 7.5.3 doesn't officially support Windows 8 and Windows 2012, and you might not be able to get support for unexpected issues you might encounter.
Regards,
Raphaël Lalonde Lefebvre