I've been trying to get kdm's autologin to work, but am having a bit of difficulty. When it tries I get an "Authentication failed" messagebox, after clicking on it everything works normally though, just no autologin. I've got kde 4.2.2 compiled from source here, installed in /usr/local. To start kdm I've more or less just slightly modified kubuntu 8.10's /etc/init.d/kdm script, so it should grab the right files (ie: /usr/local/bin/kdm instead of /usr/bin/kdm, /usr/local/share/config/kdm/kdmrc for kdmrc, etc). Just for kicks I tried the "passwordless login" for my user also, and it behaves the same. I didn't see anything that looked very interesting to me in /var/log/kdm.log, but /var/log/auth.log does give lines like this:
Apr 7 07:57:48 terra kdm: :0[6576]: pam_unix(kde-np:auth): authentication failure; logname= uid=0 euid=0 tty=:0 ruser= rhost= user=blackwaltz

Any ideas?