All those folders cannot be called Administrator
They either have different names, or you are referring to accounts that have administrator rights.
More details might help. Also, how many accounts are showing on your login screen? How many show in the USERS area of Control Panel?
They could be created by a virus or spyware. You could one at a time, try to rename the folder. If it is a real windows folder, you will not be allowed to rename it, if it is not being used by the OS you will be able to rename it.
Don't try to rename your own folder, regardless. If there is a glitch you could get locked out of windows.
Don't rename the "administrator" account either.
In my c:\Documents and Settings, there are 17 (seventeen) Administrator account folders in addition to my own account, All Users, and Default User. I've run System Restore quite a few times over the past year, so could this have anything to do with it or is something wrong here?