Some once you will found some entries can not be remove, this entries will be write in errorlog.txt file.
If all erro code is 0 in the error file. This means that the process of running not occurred error. Usually this issue is because:
1. User account without adequate privileges.
2. These keys used by some application, or some application opened these keys and do not close them.

Solutions:
Since Windows 2000, every registry key can be set up a special privilege, frist, you need make sure the issue whether caused by privilege. Please follow following steps to make sure the reason:
1. Open your errorlog file and remember the position of the first key.
2. Press "Win+R" (Or click start -- Run) input regedit, and go to this key.
3. Right-click and choose "Permissions".
4. Choose your user group at above of Permissions dialog box.
5. Check the privilege of your user group. If Allow "Full Control" checked, it's good. If Allow "special Permissions" checked, you can make sure the issue caused by not adequate privilege.
If all keys that on your errorlog file is good ("Full Control"), then you can try run WRC in Safe Mode, else this is a adequate privilege problem, You can checked "Full Control" to solve this problem, then run WRC again.