KDE-4.2-rc1 plasma instantly crashes

Since upgading from 4.1.85 to 4.1.96 plasma doesn't start at all. When I try to manually start it it instantly crashes again.

Jaunty, x86_64, intel GM45, Xorg 1.5.99.3

# DISPLAY=:1.0 gdb plasma # --nocrashhandler --nofork
GNU gdb 6.8-debian
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu"...
(gdb) r --nocrashhandler --nofork
Starting program: /usr/bin/plasma --nocrashhandler --nofork
[Thread debugging using libthread_db enabled]
[New Thread 0x7f2a802e1760 (LWP 15211)]
<unknown program name>(15211)/ checkComposite: Plasma lacks an argb visual 0x0 0
<unknown program name>(15211)/ checkComposite: Plasma is COMPOSITE-less on 0x1b94f10
plasma(15211) KServiceFactory::findServiceByDesktopPath: "findServiceByDesktopPath: not found"
QLayout: Attempting to add QLayout "" to QWidget "", which already has a layout
plasma(15211) KServiceFactory::findServiceByDesktopPath: "findServiceByDesktopPath: /usr/share/applications/kde4/Kontact.desktop not found"
plasma(15211) KServiceFactory::findServiceByDesktopPath: "findServiceByDesktopPath: /usr/share/applications/kde/amarok.desktop not found"
plasma(15211) Solid::Control::ManagerBasePrivate::loadBackend: Backend loaded: "HAL-Power"
Object::connect: Attempt to bind non-signal TaskManager::TaskGroup::editRequest()
QCoreApplication::postEvent: Unexpected null receiver
[New Thread 0x7f2a61ed9950 (LWP 15215)]

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7f2a802e1760 (LWP 15211)]
SystemTray::FdoSelectionManager::initSelection (this=0x1fd4740)
    at /build/buildd/kdebase-workspace-4.1.96/plasma/applets/systemtray/protocols/fdo/fdoselectionmanager.cpp:277
277 /build/buildd/kdebase-workspace-4.1.96/plasma/applets/systemtray/protocols/fdo/fdoselectionmanager.cpp: No such file or directory.
 in /build/buildd/kdebase-workspace-4.1.96/plasma/applets/systemtray/protocols/fdo/fdoselectionmanager.cpp
(gdb) bt
#0 SystemTray::FdoSelectionManager::initSelection (this=0x1fd4740)
    at /build/buildd/kdebase-workspace-4.1.96/plasma/applets/systemtray/protocols/fdo/fdoselectionmanager.cpp:277
#1 0x00007f2a64943550 in SystemTray::FdoSelectionManager::qt_metacall (this=0x1fd4740,
    _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fff88318dc0)
    at /build/buildd/kdebase-workspace-4.1.96/obj-x86_64-linux-gnu/plasma/applets/systemtray/moc_fdoselectionmanager.cpp:78
#2 0x00007f2a7b86f154 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#3 0x00007f2a7b8753bf in ?? () from /usr/lib/libQtCore.so.4
#4 0x00007f2a7b869a63 in QObject::event () from /usr/lib/libQtCore.so.4
#5 0x00007f2a7bf7ebfd in QApplicationPrivate::notify_helper () from /usr/lib/libQtGui.so.4
#6 0x00007f2a7bf869ba in QApplication::notify () from /usr/lib/libQtGui.so.4
#7 0x00007f2a7e56933b in KApplication::notify () from /usr/lib/libkdeui.so.5
#8 0x00007f2a7b85ad81 in QCoreApplication::notifyInternal () from /usr/lib/libQtCore.so.4
#9 0x00007f2a7b886ac6 in ?? () from /usr/lib/libQtCore.so.4
#10 0x00007f2a7b88322d in ?? () from /usr/lib/libQtCore.so.4
#11 0x00007f2a76b3d1db in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#12 0x00007f2a76b4099d in ?? () from /usr/lib/libglib-2.0.so.0
#13 0x00007f2a76b40b5b in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#14 0x00007f2a7b88318f in QEventDispatcherGlib::processEvents () from /usr/lib/libQtCore.so.4
#15 0x00007f2a7c010adf in ?? () from /usr/lib/libQtGui.so.4
#16 0x00007f2a7b8596a2 in QEventLoop::processEvents () from /usr/lib/libQtCore.so.4
#17 0x00007f2a7b85982d in QEventLoop::exec () from /usr/lib/libQtCore.so.4
#18 0x00007f2a7b85bcdd in QCoreApplication::exec () from /usr/lib/libQtCore.so.4
#19 0x00007f2a7feb86cb in kdemain (argc=3, argv=0x7fff88319a38)
    at /build/buildd/kdebase-workspace-4.1.96/plasma/shells/desktop/main.cpp:54
#20 0x00007f2a7ac08586 in __libc_start_main () from /lib/libc.so.6
#21 0x00000000004007c9 in _start () at ../sysdeps/x86_64/elf/start.S:113
(gdb)