The folder GMAP is for PC....and with the program MapSource or MapInstall, the shortcut-map send to device or SD.

You have to follow this tutorial [Only registered and activated users can see links. ]
Extract:
Have you downloaded a Mapsource Gmap folder ?


copy it in:
(in XP - C:\Documents and Settings\All Users\Application Data\GARMIN\Maps) or
(in Vista, Windows 7 - C:\ProgramData\Garmin\Maps)
You'll have your map in Mapsource.
To unlock use:
[Only registered and activated users can see links. ]
or
[Only registered and activated users can see links. ]
After [Only registered and activated users can see links. ]
....and other tips [Only registered and activated users can see links. ]

Or use map Locked IMG (Unlock with gimgunlock r.0.3) or Unlocked IMG....just for your device.

Bye,bye