If on an IBM 5150 switch block SW1, switch 1 is enabled, you indicate that there are no floppy controller or floppy drives present. So it is no longer necessary to check for the presence of a floppy controller or floppy drives. The check now seems to be performed and therefore generates an error message if no floppy controller is present.
In my IBM 5150, the floppy controller's place has now been taken by a PicoMEM.