From the community knowledge article on how to setup the quickstart vm:   4. Some users have reported problems running CentOS 6.4 in VirtualBox. If a kernel panic occurs while the VirtualBox VM is booting, you can try working around this problem by opening the Settings > System > Motherboard tab, and selecting ICH9 instead of PIIX3 for the chip set. If you have not already done so, you must also enable I/O APIC on the same tab. ... View more