Zigg,
I've downloaded and used both gpsunderground links (Rapidsare and Megaupload) map downloads, deleted my outdated map, renamed the new maps and saved them to my PDA. Did not work so I reinstalled my old map (version 675.1431) but I get the same No Map error message.
Something went wrong...
Pay attention, because lot of user prevent of a new public works in one street, but never make modification when the public works are done.
My advice is to never use the mapshare.