Version:            (using KDE KDE 3.5.8)
Installed from:    Ubuntu Packages
Compiler:          GCC 4.x 
OS:                Linux

I haven't been able to reproduce this again.  However, there's a decent backtrace below.

If it helps, there was a Wine application on systray too.  When Kicker crashed that application's icon moved to a separated window where it stuck even after Kicker reloaded.  I'm not sure if it's related, but the more info the better, right?

Using host libthread_db library "/lib/tls/i686/cmov/libthread_db.so.1".
[Thread debugging using libthread_db enabled]
[New Thread -1233336096 (LWP 5714)]
[KCrash handler]
#6  0xb5f0090a in TaskContainer::updateKickerTip (this=0x831dc08, 
    data=@0xbfa7f7f4)
    at /root/kdebase/kdebase-3.5.8/./kicker/taskbar/taskcontainer.cpp:1560
#7  0xb6507f92 in KickerTip::display (this=0x81bb180)
    at /root/kdebase/kdebase-3.5.8/./kicker/libkicker/kickertip.cpp:129
#8  0xb650850f in KickerTip::qt_invoke (this=0x81bb180, _id=48, _o=0xbfa7f93c)
    at ./kickertip.moc:91
#9  0xb71d788b in QObject::activate_signal (this=0x81bb254, clist=0x81bccd8, 
    o=0xbfa7f93c) at kernel/qobject.cpp:2356
#10 0xb71d8330 in QObject::activate_signal (this=0x81bb254, signal=2)
    at kernel/qobject.cpp:2325
#11 0xb7565876 in QTimer::timeout (this=0x81bb254)
    at .moc/debug-shared-mt/moc_qtimer.cpp:82
#12 0xb71ff596 in QTimer::event (this=0x81bb254, e=0xbfa7fc68)
    at kernel/qtimer.cpp:219
#13 0xb716ea60 in QApplication::internalNotify (this=0x808f5b0, 
    receiver=0x81bb254, e=0xbfa7fc68) at kernel/qapplication.cpp:2635
#14 0xb717088f in QApplication::notify (this=0x808f5b0, receiver=0x81bb254, 
    e=0xbfa7fc68) at kernel/qapplication.cpp:2358
#15 0xb785dac2 in KApplication::notify (this=0x808f5b0, receiver=0x81bb254, 
    event=0xbfa7fc68)
    at /root/kdelibs/kdelibs-3.5.8/./kdecore/kapplication.cpp:550
#16 0xb71011e9 in QApplication::sendEvent (receiver=0x81bb254, 
    event=0xbfa7fc68) at ../include/qapplication.h:520
#17 0xb71614ab in QEventLoop::activateTimers (this=0x80e1930)
    at kernel/qeventloop_unix.cpp:556
#18 0xb7115d25 in QEventLoop::processEvents (this=0x80e1930, flags=4)
    at kernel/qeventloop_x11.cpp:389
#19 0xb7189136 in QEventLoop::enterLoop (this=0x80e1930)
    at kernel/qeventloop.cpp:198
#20 0xb7188f46 in QEventLoop::exec (this=0x80e1930)
    at kernel/qeventloop.cpp:145
#21 0xb7170609 in QApplication::exec (this=0x808f5b0)
    at kernel/qapplication.cpp:2758
#22 0xb660cda2 in kdemain (argc=1, argv=0x80a4ec0)
    at /root/kdebase/kdebase-3.5.8/./kicker/kicker/core/main.cpp:149
#23 0xb7ef7464 in kdeinitmain (argc=1, argv=0x80a4ec0) at kicker_dummy.cpp:3
#24 0x0804e67f in launch (argc=1, _name=0x808b3a4 "kicker", 
    args=0x808b3ab "", cwd=0x0, envc=0, envs=0x808b3af "", reset_env=false, 
    tty=0x0, avoid_loops=false, startup_id_str=0x8050fee "0")
    at /root/kdelibs/kdelibs-3.5.8/./kinit/kinit.cpp:673
#25 0x0804ef02 in handle_launcher_request (sock=9)
    at /root/kdelibs/kdelibs-3.5.8/./kinit/kinit.cpp:1240
#26 0x0804f2d8 in handle_requests (waitForPid=0)
    at /root/kdelibs/kdelibs-3.5.8/./kinit/kinit.cpp:1443
#27 0x08050563 in main (argc=5, argv=0xbfa806c4, envp=0xbfa806dc)
    at /root/kdelibs/kdelibs-3.5.8/./kinit/kinit.cpp:1908
#28 0xb7c62ebc in __libc_start_main () from /lib/tls/i686/cmov/libc.so.6
#29 0x0804bb51 in _start ()