Beginner KDE question

["Shockley, Steve" <Steve_(_dot_)_Shockley_(_at_)_Scala-NA_(_dot_)_com>]

I finally got KDE to work by installing from Ports, and running KDE from the
command line (with exec startkde in the .xinitrc) using startx works great.
However, if I enable xdm, after login (as root) the screen blinks, then
returns to the login.  I've got an ~/.xsession with exec startkde in it, and
it's got execute permissions.  The first problem reported in
.xsession-errors was "startkde not found".  So, I changed it to "exec
/usr/local/bin/startkde", and now I get a bunch of messages like "kcontrol:
not found".  It sounds like a search path problem, and there's probably an
easy fix.  Anyone know what it is?  I'll be happy to R the FM if you point
me to it...