That's just a generic error message that doesn't really mean anything. Do you have the bios in the right spot and have you tested the rom on another retroarch device?
Some people don't want Nintendo seeing them using unauthorized programs. Using Rosalina it doesn't show up in activity log. I personally just use cias but I understand the paranoia.
Shouldn't have said "that's it" because there are many less demanding games that can run from any system. All depends on the game you want to play. Personally I had a lot of slow downs playing GBA so I used injections instead until I got my n3ds, but ymmv of course.
@JasonPK92 I have had...
You have to open another core before retroarch.cia will work. It only opens the last used core but if you haven't opened one it doesn't know what to open.
Shawnita used to get her pills from some other street pharmacist and after switching to The Psi Discount plan she now only has to swallow two things a day!