As I hoped the admins at rapidvps.com got back quickly, and they have diagnosed the problem as fault in the raid controller.
Until I can be moved onto a new server, they have kindly provided me with hosting elsewhere for the maps.
So map downloads are now working
In other news,
Trap Up and Down version 2 by DTM Racer is now available, and is on the server. This I have to say is a big improvement over the first, not only in looks, but also in layout and playability.