It is against the rules to ask where to get roms. Sounds like you might want a torrent. Type "neogeo torrent" in google - you may be surprised at what appears.
The only question I can answer is that the current version is 20.3 It is not an "open-source" project, only a few versions have had sources released. What compiler, libraries, etc are needed I have no idea.
You have a right to make a backup. You don't have a right to play it on your pc. Bill Clinton never made such a law, what you see on some rom sites is utter fiction.
I've seen so many phpBB sites wiped out from hacker's attentions (although mostly last year), certainly if I was to have a forum it wouldn't be that brand. I note the site is called Vote For The Worst - they'll be able to vote for themselves soon enough I imagine.
So it was caused by webmasters who didn't take the most basic precautions. Huh. Here the post referred to: http://www.vftwforum.com/phpBB2/viewtopic.php?t=907