> >This was a disaster. The window came out nicely and when I enter
> >the username and passwd it blinked out, and came again prompting
> >me, and again and so on. I had to use de middle finger to reset
> >the machine! Is there anything that I forget to do?
> 
> Sounds like your .xsession file is messed up.  Try moving it out of
> the way.

A handy thing for .xsession debugging is to use xdm's failsafe mode,
using f1 or control-return to log in. Then look in .xsession-errors.

[note the failsafe key can be changed in xdm's Xresources, but I 
 believe f1 and control-return are the defaults for NetBSD.]