I have Popper running in non admin now, and it seems to work. I'm not sure why Nailbuster has this admin requirement in his FAQ/Troubleshooting guide.
Great! Yeah, "run it in Admin mode" is one of those generic pieces of advice that people hand out, but it's really mostly outdated, and it tends to cause more problems than it solves. There are probably still a few special situations where it's needed, but those are getting fewer all the time as the software improves, so the FAQs that say "Admin Mode Everywhere All The Time" really should be updated to be more nuanced.