Quoting ParagonRenegade, reply 1
Do you have a 64-bit OS? That's what happens when you don't :C
A 64-bit OS is absolutely critical.
My Mavericks is 64-bit, but the virtual machine WinXP I'm running might be not. Silly thing to miss!
XP isnt supported nor are any Macs
You will need
1) Windows 7 or Windows 8 64-bit (32 bit is NOT SUPPORTED)
2) A DX10 compatible video card