r.contour

[julied at robinhood.ssmc.noaa.gov]

   I am working with r.contour on IBM RS/6000s. Sometimes when using r.contour,
for no apparent reason, as the routine is running, it suddenly says
"killed". We can not find a pattern of when r.contour runs successfully and
when it gets killed.
   Has anyone else had this problem, or does anyone know how to resolve it.
Thanks in advance.
Julie Daniel