i am also using Win 7 ultimate x64 and had no problems at all installing or "cracking" Vue ( personal i don't class a keygen as a crack, as its not cracking anything, its just giving you a serial number)
I followed the instructions given by Xforce and all went perfect, Altho i never lost internet connection like Pmaggia said would happen, because he tells you go to network adapters and Fill in a number, then copy that number. YOU SHOULD NOT DO THAT. you already have a mac address all you need to do is call up your mac address using ipconfig commands from command prompt. In fact going back and looking at the README its way different to what pmaggia has told you to do. so no wonder he lost internet connections.... heres what the readme ACTUALLY says..
so to get your Mac address on Windows you go to the start menu and type CMD ( then press return ) a dos prompt window will now open, so type " ipconfig/all " minus the " symbol. it will list several things the one you need to find is the " Ethernet adapter local area connection" then look in that section for the " Physical address...." it will be 6 pairs of digits.. as an example 01-af-2d-9f-42-f6 . so in this example when you need to input the address into the activation you would use 01AF2D9F42F6.
THAT should be the only thing stopping you from activating this, if your doing that correctly and its still not activating for you, id say you have screwed up somewhere REALLY badly. as others have said Vue is one of the easiest things to activate as you are NOT cracking anything you are just inputting a few numbers. the same as you would need to do if you owned a legit version of the program.