Ticket closed. It was a DLL specific problem (not caused by SetupBuilder). The installer loads the DLL and calls the "DllRegisterServer" API to execute the self-registration process. In case this process fails, the installer retries it with another self-registration option. Problem is that, although this DLL fails to create all registry items, it returns SUCCESS. We have modified the SB runtime source code to handle this specific scenario in the next maintenance build.