First off, I hate Ubuntu and I'm not great with command line stuff. I had a legit NuCore a few years ago. That was no easier to set up. I haven't tried it in the game yet, so I'm not certain it works, but I can boot into RFM, so I'm somewhat confident I'm most of the way there.
A few people have posted the fix that snags some updated files. Unfortunately the command line is really long, and if you miss anything the whole thing is a waste. I was able to get to the desktop, or whatever Ubuntu calls it by typing
lxdm start
From here I figured I could go to the browser, head back to pinside, copy and paste and be done. Not so fast! I got some weird error when trying to run Chromium. I decided to try and mess around with "Configure Pinbox" on the desktop. This worked and also has an address bar. Typed in pinside and it worked! Searched up this thread, opened up "LXTerminal" and copy pasted these commands from a few posts above (thanks andrewhannay !)
sudo su
sudo sed -i -re 's/([a-z]{2}\.)?archive.ubuntu.com|security.ubuntu.com/old-releases.ubuntu.com/g' /etc/apt/sources.list
sudo apt-get update
apt-get purge lxdm
mv /etc/lxdm /etc/lxdm.orig
apt-get install lxdm
cp /root/pinbox/scripts/pinbox.desktop /etc/xdg/autostart
rm /etc/init.d/pinbox
reboot
Not every command seemed to do something but I copied and pasted every one anyway and in the end I got to a mirror of the choose game screen. Going back to "Configure Pinbox" and manually choosing the game I was able to get both games to the attract screen. I'm not sure about my PCI-E paralell card yet.