Hi,
There is no need to have a registered FSUIPC key. You can download FSUIPC, install it and run Flight logger.
There is also a Microsoft DLL file that you need to install to not get the "Type mismatch" error if you turn on your engines and flight logger is already running.
You can read all about this on a Topic Forum created by Armando Chibante (Flight Logger owner).
Regards,