[GRASSLIST:3150] d.colormode float

[DeanRNet6 at netscape.net]

Howdy,

Just installed GRASS.  I'm a newboot, forgive me.  I'm pretty darn good 
GISer though.
So, I'm using MacOSX 10.1.2 because I need a break from Windoze, VB and 
ESRI on occasion.  I'm having trouble with d.colormode float.

When I type it at the command line
 >GRASS 5.0.0pre3 > d.colormode float

I get the following message:
 >WARNING: Color_table_float: not available on this device
 >Sorry, floating color table not available on this device

So here I am following the tutorial and it tells me this:

Display the satellite image again.

 >Commands :
 >
 >d.mon select=x0
 >d.rast image

Which I do.

 >Discussion The image should consist of approximately 8 shades of grey 
- enough >to identify most of the features of the study area. As GRASS 
is capable of >displaying up to 240 colours on an most workstations, why 
are there only 8 grey >shades making up this image? GRASS has a fixed 
palette of colours all of which >can be displayed simultaneously. Since 
an image can consist of any range of >colours, only a few can be 
reserved for grey scales. GRASS simply matches each >raster cell value 
to the nearest available colour.

 >We can produce an improved image by abandoning GRASS' fixed palette 
and >dedicating most of the range of colours to one image.

 >Make sure the pointer is resting over the graphics window x0.

What exactly does this mean.  If my cursor is over the window x0, then I 
can't type 'Enter' and have the terminal window respond.

 >Commands :
 >
 >d.colormode float
 >d.rast image
 >
 >Discussion You should see an improved satellite image of the study 
area. The >majority of the workstation's colours have now been allocated 
to grey values in >this one window. When using this floating colour 
table, GRASS allocates the >correct colours to the window on which the 
pointer is resting.

So I type d.colormode float and get the error I mentioned before.

Anybody have any insight on this? 

Thank you,
Dean