Your question isnt so clear, what do you mean for gmap.img 2012.10?
Anyway ,have your copied it your *.img in "Map" folder as anyname.img ?
gmapsupp.img wont work in "Map" folder , neither in unit memory nor in sd.
Have you checked with Gmaptool the map is really unlocked ?
Have you any other routable .img in your device covering the same area ?
Nuvi wont show correctly 2 routable maps covering the same area, so if you have an older map , backup it on pc and delete it
Try to be more precise writing about your problem