[Groff] Installing/Running on W7 x64 groff-1.20.1

[John W. Smay]

I am loading up a new Windows 7 x64 (64 bit) computer, in particular with groff.
1) Is there a groff build specifically for Windows 64 bit?  I could not find 
one so I downloaded "groff-1.20.1-setup.exe" and "installed" using
this program from 
http://sourceforge.net/projects/gnuwin32/files/groff/1.20.1/groff-1.20.1-setup.exe/download?use_mirror=superb-dca2
 .

2) When I try to run, I get error 
grops:<standard input>:4:fatal error: fdopen: Invalid argument
troff: fatal error: error writing output file
Can someone help with this?

Support info:  The following confirms the installation:
smay8% which groff
C:/Applications/groff-1.20.1/GnuWin32/bin/groff.exe
smay8% groff -v
GNU groff version 1.20.1
Copyright (C) 2009 Free Software Foundation, Inc.
GNU groff comes with ABSOLUTELY NO WARRANTY.
You may redistribute copies of groff and its subprograms
under the terms of the GNU General Public License.
For more information about these matters, see the file named COPYING.
called subprograms:
GNU troff (groff) version 1.20.1
GNU grops (groff) version 1.20.1
Following, fp is my script to sequentially call tbl, eqn, and groff -ms and 
exhibit the error message
smay8% fp -s apD
grops:<standard input>:4:fatal error: fdopen: Invalid argument
troff: fatal error: error writing output file
smay8%
----------
Remark: groff-1.17.2 appears to run satisfactorily on both my old (32 bit) and 
new (64 bit) computers.

Thanks, John