Loads Of Cache

Please can someone help out? I have just bought a GPSmap 60Cs (second hand) and i have got mapsource on my pc working, with city select (the one which navigates for you - found this out the hard way!!) The map detail is unlocked, but when i send the map to my GPS, it says that it cannot unlock the map. What can i do to unlock it on the GPS, dodgy or non-dodgy methods Thanks LoC

Hey perdix Pinky from LOC here. Will not be coming to PE. Trip cancelled again. Will be placing TB up in Joburg. Thx