Have you check the arp table on the targets?
Are you trying to attack a computer which is hosting the VM? I had problems when doing this. Try in another VM, or a whole new PC.
and when you say "404" error, what URL are you trying to view? Because it only works with top level domain. You will need to modify apahce2 I believe if you want it to work with sub-domains, subfolders kinda deal! *its on the to-do list*