I have a desktop computer running the latest Ubuntu 12.10 32-bit. I'd like to run RHEL 5.5 64 bit in Virtualbox (4.1.8). However, when I bootup the VM with the CD, I got "You CPU doesn't support long mode, Use a 32 bit distribution.".
The CPU I have is Intel Core i7-3770.
In the system config, I can see that "Enable VT-x/AMD-V" is checked.
What can I do?