lembas, GustavoCM:
Those solutions did not work for me, and doing a web search is leading me to
areas that are too complicated for me to tackle. It seems my case is
sufficiently atypical that the only way to (possibly) fix it would be to
re-compile the kernel. Too much work.
Qemu seems to work, so I think I'll try putting my efforts toward figuring
out its nuances. I don't exactly need VirtualBox, just virtualization.
Thanks for the help at any rate. Hopefully this thread helps somebody else
with a more common setup.