Having been running KDE4.1 on OpenSUSE 10.3 for a couple of months,
I've suddenly developed a problem; sometimes, it is impossible to
start K-applications from the graphical user interface (and sometimes
even from the command line). Usually the session begins OK but then
you lose them. Kontact is the least vulnerable and Kate probably the
most. KDE3 applications launch correctly. Error messages relating to
DCOP and DBUS are sometimes thrown. Non-KDE applications (Mozilla
Firefox, Skype, OpenOffice, GIMP, the Python virtual machine..) work

..xsession-errors contains a reference to "149: File retriever failed"
for each nonlaunch, which is a google deadspot.