It is unusal that it should be a problem with permissions, on a default install. Java, for example, reuires no such permissions. Somtimes the reason can be a corrupted licence file, such as removal of the efi.cfg, or the use of one of the various posted methods of delaying activation indefinitely.
I think the easiest way to try to overcome the problem, is to log in with a Global Admin account. To do this, there are a couple of different ways:
Open a command prompt (Run as Administrator).
Type the following command and enter.
net user administrator /active
Log out and see if you have a new alternative login, as well as your existing one. If not, do it the long way.
Shut down the computer for a cold boot. Tap the "F8" key as you are booting.
Select "Safe Mode with networking" from the boot menu.
Log into windows 7 with your personal account that holds the administrator access.
Open a command window (START--->RUN--->CMD.exe). At the command prompt type the following net user administrator /active
Log out and log back in as administrator.
Another way
Go to Start
Type Control UserPasswords2.
Click Advanced.
Click Advanced again.
Select Users.
Select Administrator and untick the the box “Administrator is disabledâ€Â
Now log out and login as Administrator.
I would suggest, assuming this works for you, that when you have finished installing, you log back in and disable the Admin account again. For the unwary it can give you too many open priviliges.