Hi, Pete:
I just installed Windows 8 Release Preview a few days ago, then installed Flight Simulator X and Service Packs 1 and 2. No other add-ons are installed yet
I'm having the same problem trying to run the installer for FSUIPC4. When first launching the application, I get the standard User Account Control prompt asking me if I want to allow the program to make changes to my computer. After approving, and then a window titled "Installer for FSUIPC 4" opens. It only gets as far as displaying the text "Installer for FSUIPC4.DLL version 4.827" before I get an "FSUIPC4 installer for FSX has stopped working" dialog box. Like the OP, I've tried running it as an administrator and in compatibility mode for Windows XP, Vista, and 7, with no luck.
How can I access my Windows application log?