Traceback (most recent call last):
  File "/usr/local/grass-6.5.svn/etc/wxpython/gui_modules/gd
ialogs.py", line 528, in OnOK

self.parent.MapWindow.UpdateMap()
  File "/usr/local/grass-6.5.svn/etc/wxpython/gui_modules/ma
pdisp_window.py", line 840, in UpdateMap

for img in self.GetOverlay():
  File "/usr/local/grass-6.5.svn/etc/wxpython/gui_modules/ma
pdisp_window.py", line 699, in GetOverlay

if os.path.isfile(overlay.mapfile) and
os.path.getsize(overlay.mapfile):
  File "/usr/lib/python2.6/genericpath.py", line 29, in
isfile

st = os.stat(path)
TypeError
:
coercing to Unicode: need string or buffer, NoneType found