For those not subscribed to bug 965242, there seems to be a workaround.
Add the following somewhere at the beginning of /opt/kde3/bin/startkde:
GAM_SERV=`pgrep gam_server` if test -z $GAM_SERV ; then echo "No gam_server running, starting it..." /usr/lib/gam_server& fi
It looks like KDE3 starts OK when gam_server is already running and crashes when gam_server is not running when kded/kdesktop/kicker call FAMOpen. I could not find how gam_server is started. Possibly, libfam0 starts it when called for the first time. So probably KDE3 can't handle correctly this situation.