Most of the icons in the "Futurosoft" set you've linked look like they were ripped from various sources (mostly from Windows 7, with a few from OS X). It looks like the set was syndicated from kde-look.org, and I've shot them a message about the situation.
They were syndicated from Futuresoft - I will look them through and remove those from OS X and Windows.
None of the icons were specifically from Win 7 since Futuresoft was released many years ago.
Strange - looking at a lot of the icons, like the ones following, they certainly must have been designed to resemble Windows icons, but I can't find the exact icons they're modeled after. I'm really not sure where these would stand, as far as copyright goes - a number of them have enough resemblance to real Windows icons (or other trademarks) that you'd probably get legal grief for trying to use them in your own product, for instance.
Examples:
http://www.iconfinder.com/icondetails/7395/128/finder_mac_wi... (XP wallpaper, listed under GPL license)
http://www.iconfinder.com/icondetails/7512/128/application_a... - Apple's icon