Never heard of this error, either.
First thing I'd double-check, are the BIOS settings, though. Is it possible that the battery went empty, and you encountered the "Authorization" prompt after that?
If so, this could have messed up what IRQs are reserved for the serial ports etc., and I could imagine that this might lead to a PIC Interrupt error, when booting from the floppy installer disc (I know it doesn't give that error when booting from the harddrive... just wondering if the OS loaded by the floppy uses different error handling and thus different messages).
Pino68:
It sounds like you already have a 2nd harddrive with MackieOS 5.1 on it. Did you try connecting that to your "regular" computer, renaming the original "MackieOS.exe" (for example to "MackieOS.old", then extracting the file I shared above, making sure the extracted file is renamed to "MackieOS.exe" and putting it in the place of the "old" one?
Then you'd install the drive back into the D8B rack case, and boot up the unit.
As long as the BIOS settings are right, it should just boot up after that (and NOT give an authorization error).
If you have the drive out and can connect it to another computer, that's a simpler way to replace the original MackieOS.exe file with the hacked version.
What made this so complicated in my earlier post, was just to copy the file to the harddrive via the floppy drive, and having to compress/extract and rename the file to make this workaround of an approach function.
Anyway... if you feel that you MUST install the OS, I'd recommend to double-check the BIOS settings and try to install from the floppy drive again.
Upgrading your D8B hardware is of course also a good idea, as Doktor1360 suggests. It's up to you, how big a project you want to turn this into at this moment.
Personally, I'd probably try to get basic functionality working for the D8B first... and when you know that works, that's when I'd set aside some time to upgrade the unit in a separate step.
Anyway... it's up to you. If you want to do the upgrades now, I'll just stay out of it this time... I keep thinking that I'm just causing confusion when I keep chiming in and suggest something different than what was suggested by others before.
So - I'll stay out of it from now on - best of luck with getting this working, Pino68!