OK…
So, I uninstalled System Ninja, then using RegEdit, I removed all references to System Ninja from the registry.
Then re-booted the laptop, re-installed from “ninja-setup-3.2.5.exe” running as administrator.
Than ran System Ninja, ‘ as administrator’, went to the ‘Options’ tab and selected ‘Debug Mode’, and tried using ‘Junk Remover’, the problem is still just the same.
I opened the System Ninja folder but this time ‘ debug-errors-***.log’ is absent.