DRAWING

You should be checking SYSTEM(_maxColors). That will let you know if their machine is capable of 256 or more colors. It checks only the main monitor, but that should be good more than 99% of the time. How many people really have more than one monitor hooked to their Mac?

LONG IF SYSTEM(_crntDepth) <> 8
  LONG IF SYSTEM(_maxColors) => 8
' change to 256 colors
  XELSE
    BEEP ' Tell user they need a Mac capable of at least 256 colors
  END IF
END IF