@Ghosty_Slo
What was commonly called 'mapsource' [or map source] data version is now usually referred to as 'PC version' or 'PC Install' which is less confusing because MapSource [the program] which uses 'map source data' is now defunct and unsupported anyway.
You can install the 'PC Version' [first link in Post #1] or you can simply open it, find the gmap folder and drop it into the correct loction for your OS and it will be found by the BaseCamp & MapInstall & MapSource programs [but don't use the old MapSource program for making of any modern City Navigator map including EU 2014.40 or you may have errors in the compiled image].
Default gmap locations:
Win XP - C:\Documents and Settings\All Users\Application Data\GARMIN\Maps
Vista, Windows 7/8/8.1 - C:\ProgramData\Garmin\Maps
Bookmarks