Hello,
I have the same problem like jrafols. I have all 29 files, but there is a error in a file. I canŽt extract the map.

Teste Archiv: garmin_topo_us.part01.rar.
Startzeit: 28.07.2010 08:06:26.
____________________________________________

Teste Datei: Disk1.cab OK
Teste Datei: Disk2.cab FEHLER
____________________________________________

Test abgeschlossen,, 1 Fehler gefunden.
Endzeit: 28.07.2010 08:08:35.

But iŽll try the other link: you can also download these maps that are 24k --better maps and free

Edit:

Wait, i have it. There was a error with the file part28.rar. I downloaded it again, and now it works. Thank you very much for the map!