Hi Jeffery,
Yes, likely the problem is your hardware or its settings. Here is the virtualbox documentation for requirments to run a 64bit guest (see sectoin 3.1.2 and the linke to section 10.3):
https://www.virtualbox.org/manual/ch03.html
Also, this thread might be helpful:
http://askubuntu.com/questions/41550/how-do-i-run-a-64-bit-guest-in-virtualbox
Cheers,
Ryan Elliott