the thing with Win 7 and vista is that even if you run as admin it sometimes picks folders where you CANNOT extract directly to them, instead what you can do is this, two options, one restores the ability to extract to the maps folder, the other is lengthy (only by an extra step or 2) but still allows you to drag drop the maps provided you are an admin :|

to be able to extract to the map folder in your Custom ED folder follow these steps (should)

*locate the maps folder in your custom edition folder and right click
*click "properites" and then hit the security tab
* locate your username (NOT THE ADMIN, YOU AS A USER) and click off the Read/write access permission if its not checked off
* or click "all access"
*apply changes
*enjoy being able to extract to the maps folder once again