I wasn't actually looking for the "old old archives", I assumed -- for some mentally bewildered reason -- that the post-OSC regime forum was hiding in there, and that's where I needed to go. And having gone to the wrong place and got a server error message, rather than any content or notice that made it obvious I'd gone the wrong way, backing up and going to the right one, I kept doing the same thing, and expecting different results.
So I wasn't looking for the actual archives to be retrieved, just suggesting the error message be tidied away in some manner.