Seeing as this is all the rage just now, I figured I'd report that I
recently found my KDM4 was unable to load any sessions.

I tracked this down to the fact I had a:
/usr/share/config/kdm/kdmrc.rpmnew
file. Renaming the active config made things magically work.

HTHs

Col

--

+--------------------------+
|    Colin Guthrie     |
+--------------------------+
| cguthrie(at)mandriva.org |
| http://colin.guthr.ie/ |
+--------------------------+