I was plagued with this.. you should only have one account ie administrator. If you have more than one account delete all but the default Profile and the Administrator properly via the User Profiles Tab in System Properies.
If you only have the both listed check to see if you have another profile listed in your regsitry profile list HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList
You will find a number of default profiles there but there should only the Administrator account you used to configure the profile. It will be named under ProfileImagePath C:\Users\administrator.
Copy Profile in Sysprep fails if there is more than one profile entry here.
Another time I saw this error was when I was using the a token replacement to use the BIOS Asset Tag as the Computer Name.. which in this case was blank in the BIOS after an engineer swopped the Mother board out and left the Asset Tag blank.
Hope this helps.. I got to really hate this error as originally I was blaming the Token replacement :(