During the setup of Registry Explorer, a message is displayed similar to this:
TGSETUP CAUSED AN INVALID PAGE FAULT IN MODULE MFC42.DLL.
The setup then stops without completing.
This problem occurs when older versions of the MFC libraries are installed on the system and are in use.
The setup tries to install the newest version of the MFC libraries, and then in a later phase uses them.
When the MFC libraries are present and being used by other applications, they can only be replaced when rebooting, but are still used in the later phase.
You can find a setup for the MFC libraries from microsoft at this location.
Run this setup, then run the Registry Explorer setup again.