you would be placing the maps in the OLD program files galaxy folder, you should be placing them in the NEW galaxyforge folder next to your mods folders
here is the detailed advice
the galaxy forge maps NEED to be placed here for xp
C:\Documents and Settings\'user name'\Local Settings\Application Data\Ironclad Games\Sins of a Solar Empire\GalaxyForge
or here for vista/windows 7
C:\Users\'user name'\AppData\Local\Ironclad Games\Sins of a Solar Empire\GalaxyForge.
NOTE the first two folders after the 'user name' are hidden , so to see them you must first click on 'tools' then 'folder options', then 'view', then click on 'show hidden files& folders' then click ok, then you will be able to browse your want to the folder. I suggest when you find the folder that you create a shortcut to it on the desktop
also the galaxy forge maps only show up in the galaxy forge tab of map types
hope this helps
harpo