From my reading of starstreak's question, it's about running an OSX
guest in Virtualbox hosted on an SP2.
Those instructions are about getting the virtualbox
host working on OSX.
My SP3 runs Virtualbox happily with XP or Linux guest OS, and the fact that startstreak gets as far as the 'startup spinner' suggests that vbox is running OK.
I suspect that the problem is really that Apple doesn't support running OSX in a VM on other platforms. From what I understand they really want you using their hardware, so to make that work you'll need to search for requirements to run OSX as Virtualbox guest, as it seems like your SP2 is already working fine.
(You could test that by downloading and running a lightweight linux).