That's because, in Windows 7, Documents & Settings does not exist!
You may see what looks like a folder for Documents & Settings, and you may also see folders for "My Documents", "My Pictures", "My Music", and so on, by they don't exist either.
Here's the rub. In Windows 7 (and in Vista), those folders do not really exist because all personal files are now in the "USERS" folder, with sub-folders for Documents, Pictures, Music,and so on.
However, a lot of software that we install still works on the older XP method of requiring folders and entries in "Documents & Settings/UserName" folders, and so Windows 7 has created what are called "Junction Points" for those folders which actually points to the Windows 7 User folders. This allows older software to still be installed.
These Junction Points are like shortcuts. They don't hold anything themselves even though it may look like there are files there. But they are shortcuts to the Users folders. That's why you do not have access to them, but you do have access to the Users folders for your account.
Does that help?