You are correct, it is not intuitive. The install went wrong or you didn't reboot after each step. Yes, it is fine to rerun the install multiple times; it just copies files to the Libs directory and sets up some ENV/ENVARC settings. All are easy to find and delete. Run the install again and after each step try a fresh reboot.
This should work unless you have an incompatible 9250 card (not likely if it came from Elbox or Amigakit). You can ask Elbox for help if you registered the Mediator, but don't expect a reply.
