Torrents... (whole different story; slippery ground)
I used a similar OS X 10.6.4 image a while ago, but it only worked in VMWare Workstation 7.1.4. I see you are trying to boot with VirtualBox in "Mac OS X Server mode." trying to boot snow leopard fails because of the kernel drivers that are required. You may have read about kexts, which are similar to "Drivers" in windows.
Hint: Mac OS X 10.6.8 now works in VMWare. I can't provide you with any further information, though, due to forum rules.