It is recommended that you create a restore point before installing new software or making any major changes to your computer. See How to create a System Restore Point in Windows 7 and Windows 8
1. Right-Click Windows Theme Installer V1.1 and select run as Administrator.
2. checklist at Shell32.dll and click Browse and search folder Shell32.dll
3. Choose Shell32.dll which suitable with your Bit Windows ( 32bit or 64bit). Click Open.
4. Then click Install Theme and restart your computer.
PATCH YOUR COMPUTER FOR ONCE.
IF YOUR COMPUTER HAVE BEEN PATCHED BEFORE, YOU SHOULD NOT PATCH THE SYSTEM AGAIN. YOU CAN CHANGE THEME WHENEVER YOU WISH.
Source:http://nikennosekai.blogspot.com/2014/04/tutorial-personalize-background.html