Owner of physical copy of FF14 1.0 - trouble entering in serial

I have a physical copy of FF14 1.0 that I never ended up using (I also took part in the ARR beta from stage 2). I'm trying to use it now but...
A) I have two serials, one on the back of the manual and one on a leaflet. Which one do I use?
B) The system seems to accept the one on the leaflet when I try to register a game in my S-E account. After entering in the code "FINAL FANTASY XIV" pops up, but I'm then told "invalid code" when I try to submit it.

Any ideas?