KDE wont start automatically

[Andrew Ingram <andrew@uk.clara.net>]

I did an apt-get upgrade today (I'm on Debian Sid btw). Thought I would
do a reboot since it had been a while and a lot had changed. When the
machine restarted, my machine did not run KDE (like it normally does),
it stayed in text mode and put me at a prompt.

Logging in and running "startx" fixed this but it meant that ssh-agent
wasn't working so I need to type in a lengthy pass phrase to get to the
other machines on my network.

What I was wondering was whether something got broken that I missed
being discussed here. I'm thinking kdm has a problem. Here is what I
tried:

dpkg-reconfigure kdm (choosing kdm out of kdm, gdm, etc). This output:
sh: line 1: /usr/bin/kde-update-menu: Permission denied
sh: line 1: /usr/bin/kde-update-menu: Permission denied
Not starting K Desktop Manager (kdm); it is not the default display
manager.

I assume that isn't too healthy! Also, /etc/X11/default-display-manager
has the contents: "10 kdm/daemon_name doesn't exist". I'm thinking that
isn't too healthy either! "which kdm" returns "/usr/bin/kdm" so that
looks ok to me. 

Can anyone help me with this? The above tests are just guessing really.
This isn't a part of the system that I know particularly well. Any help
would be appreciated.

Thanks,
Andrew