I set LD_LIBRARY_PATH. Indeed, libX11.so.4 was located in /usr/openwin/lib.
So I got past that problem. But I get another error.Graph_Set: can't open
Error - Can't set up pipe to graphics device.
Problem selecting x0. Will try once more
Error - Can't set up pipe to graphics device.the moon binary release. Any more words of wisdom?
-Stephen Dzurenko
Ocean Mapping Division
Ocean Technology Center
Graduate School of Oceanography
University of Rhode Island
Try using grass or xgrass w/ openwin, 
I have grass in a Sun Sparc with solaris 2.3 too,
if I execute d.mon out openwin the message are the same like as you..
:)
Nelson Segura Nunhez
Ingenieria Civil Informatica
Universidad de Concepcion
Chile.
e-mail address : nsegura@halcon.dpi.udec.cl