I have the same problem. I am trying to solve it for weeks now. No luck. I'm sure that I have INTEL installer, but it still reports that "ArchiCAD can not be installed on this platform"..
I dont know what is wrong. I think it has to do something with updating my system via"Software update..". I'm saying that because I could install ArchiCAD 12 last year on this machine, but I cannot do it now with same installation CD..