me too got same error, i got it to work on vmware player but only through installing windows 8 on a dvd using the windows 8 preview installation that micrososft recommends
If you have a host with VT-Support, PAE/NX Flag doesn't matter.
1: Windows 8 CP: Installations-FAQ « Borns IT- und Windows-Blog
The Error is caused because of a problem with a system file. there's nothing to do with it other than reinstalling the host operating system..
Shon John Xander
Then simply enable VT-X support in Virtualbox - both errors are gone (without reinstalling oder repairing the host os) - this is the result of several tests I run here in my environment.