Comment 15 for bug 132833

Here's how to fix the problem.....

open /etc/gdm/PreSession/Default

change the part under the comment "#Default value" from this:

 # Default value
  if [ "x$BACKCOLOR" = "x" ]; then
   BACKCOLOR="#dab082"
  fi

To This:

 # Default value
  if [ "x$BACKCOLOR" = "x" ]; then
   BACKCOLOR="x"
  fi

that worked for me, hopefully it does (and it should) for those who are having a problem with
the bug. If it doesn't work, just login under 'failsafe gnome' and reedit the file to its original state.