Please describe the problem:
Whenever I log in I am presented with the message, 

 "Do you wish to make GDM_Failsafe.XTERM.desktop the
 default for future sessions?

 Your preferred session type Default System Session is
 not installed on this computer."

If I choose 'Just log in' then I am able to log in normally (using the default
system session).

This happens to my user after I log in once with the 'failsafe xterm'
session.

The captions on the buttons are also incorrect. 'Make default' makes the
allegedly-missing default system session the default setting, and logs
me in as normal.

Steps to reproduce:
1. create a test user
2. log in with 'failsafe xterm'
3. log out
4. log in again... the message appears


Actual results:


Expected results:


Does this happen every time?


Other information:
Forwarded from <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=381239>