Well it seems to be working now, so 2 possibilities:
1. An issue on the Internet Archive's end. Every site has problems from time to time, after all. They've been going through Some Shit™ in recent times.
2. Some sort of temporary issue on our backend, likely one our tech guy caught during some sort of routine maintenance. I know he has some scripts he runs to keep some files in check (I think he once said something about a page file but I forget the specifics), so it's possible this is somehow tied to that.
Either way it seems fixed now so no worries, I guess.