This isn't a ubiquity bug (ubiquity hasn't started yet by this point). Perhaps somebody can figure out the proper way to launch 64-bit images in Virtual PC, since it seems kind of unlikely that it's entirely incapable of it?
I tried installing a 64-bit operating system on Virtual PC one time, and I found out (the hard way) that it is, actually, entirely incapable of running a 64-bit operating system.
Hello CSRedhat, instead of using Virtual PC, you may want to consider using Virtualbox instead. The software is not only far more reliable, but it can also boot and install x64 images.
I have no problem to run on VirtualBox, but it is not the solution. This increases the barrier to entry and ignore the error. This forces the user to perform additional actions, from which he can not refuse.
64-bit screenshot in attach.