Part of the problem appeared to be the permissions on /etc/qt3/qt_plugins_3.3rc:
-rw-r----- 1 root root 1051 2008-05-31 20:21 qt_plugins_3.3rc What applications use this file and how should its permissions be set? Running Debian unstable, KDE 3.5.9, kernel 2.6.25. Arthur.