The error message is a little misleading. The actual cause is an
improper setting of the slots in the Apple IIGS Control Panel.
With the older Apple IIGS (256K of RAM on the logic board), you need to set
Slot 1 to "Your Card" and Slot 7 to "Built-In AppleTalk". If you have a
newer Apple IIGS (1MB RAM), set only Slot 1 to "AppleTalk". You'll
have to restart after making the changes for them to take effect.