[GRASSLIST:4051] NVIZ - can't load raster

Greetings,
I'm having trouble getting anything displayed in NVIZ. I finally got
NVIZ compiled, thanks to Glynn Clements pointing out that my open GL
header files were broken, and I can get NVIZ to compile and load.
However, I can't get anything to display. The only message I get is the
following when I change the slider zexag (similare errors for height,
twist, etc):
 
can't read "Priv(.top2.panelarea.panels.main.midf.zexag.scale,relief)":
no such element in array

I found one reference to this message in the mail archives, which
pointed to a tcl/tk problem, but I didn't see a solution.  I'm using 
Grass 5.7 on SuSE 9.0.  I seem to have all the appropriate headers and
libraries for  tcl/tk 8.4, installed from the SuSE distribtion.  Thanks
in advance for any suggestions.
Regards,
-Andy.