It only uses Calibre for ePUB conversion. The only requirement is that the Calibre directory has been added to the environment path which should happen after installing Calibre and a restart.
I'm not sure how Opera and IE8 handles RSS/Atom feeds. Perhaps you can try using Firefox 3.5.2? You should be able to navigate the feed using Firefox.
If working from within the VM, the url should be:
http://localhost/ffnet/ or
http://127.0.0.1/ffnet/
No idea how to handle the networking, though. I use "Bridged" mode for mine so the VM gets a separate IP address. I don't think "Host Only" would work. "NAT" would probably do if you can figure out how to do the port forwarding.