How to solve the error "Code: 0x0000000A" while installing Windows 8 Developer Preview?

Windows 8 needs hardware support for virtualization, and error 0x0000000A appears to be linked with the lack of the forementionned : althrough I see that your VT-x/AMD-V acceleration is enabled, I would recommend you to double check it (especially, verify that the feature is enabled in the BIOS setting menu).