2034-09-30 Sat - Time overflow in some ancient UNIX, which was fixed long ago.

Some really old Unixes didn't have the epoch in 1970. I couldn't find an online reference to this, but in The Clock Of The Long Now Ken Thompson or Dennis Ritchie or someone like that describes his mail archives from about that time, in which he's not sure exactly when they're from because "we changed the epoch around a few times".

Peter