Have you enabled virtualization as outlined in the common issues listed on the article I linked to?
We suggest in the article to use the following method to install the VM for VirtualBox if you haven't done so already.
"For example, if you elected to use VirtualBox, you would have downloaded and extracted a *.ovf file from Cloudera. Use the “File -> Import Appliance” menu inside VirtualBox to open your downloaded *.ovf file, or simply double-click on the file itself and VirtualBox should handle it from there."
It is also important to know the resources (processors, RAM, disk) of the system you are creating the VM on as well as how much of those resources are allocated to the VM. It is a common error to assign to many or too little of the resources to the VM which can cause issues.
The Mac shouldn't have the issue but just to be sure you can go to the terminal application and enter
sysctl -a | grep machdep.cpu.features
If VMX is listed in the results virtualization is indeed enabled.
Can you share the specs on the Mac in terms of processors, RAM and Disk space as well as what was allocated to the 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.