I do....SManager, K-Manager and FlashPro Manager, all working as it should.
Check if you have admin permissions and also re-check if you dont have any AV or firewall enabled (even windows 8 firewall or any ther built in Windows security system). I did not had to use compatibility mode to install.
Also, try installing as an admin (right click at the installer icon and select "Install as administrator" or something like that (I am not using my windows 8 computer at the moment).
s300 and SManager software questions & answers