In virtualbox, give it another shot. Try a slightly larger / (root) partition size - 3.5Gb (or 4gb if you can spare it). I was running into a similar situation installing on a VM and I had to bump the partition size up a little bit to get it to work (I think I went from 3 to 3.5gb and it worked).
Also, you probably meant 512 Mb swap, but in case you really meant 512 Kb swap then that is too small to be useful. If you meant 512 Mb then you should be good.
The md5 you come up with is correct. You can find the md5 here: http://ftp://ftp-osl.osuosl.org/pub/vectorlinux/veclinux-5.9/iso-release/VL5.9-STD-Gold.iso.md5sum