> on the applications tab, there are none present

that's an installation problem.

> this crashes all plasma and reloads the desktop

can you please post a backtrace for this?

http://techbase.kde.org/Development/Tutorials/Debugging/How_to_create_useful_crash_reports

OK. Then I think this is 2 separate bugs...
One is due to the kubuntu project neon nightly packages? So I'll try to forxard it to the maintainers then...
:)

For the 'adding Quicklaunch to Desktop'.... I just tried with drag and drop: it created an empty plasmoid on the desktop. I removed it and did the same with the 'add widget' button and Plasma froze my system and did nothing. I could run the Process Viewer and saw Plasma using 85% CPU and 25Mb RAM. I waited for 15 seconds and nothing occured, so I killed it.
Not very useful for you, I imagine... so I'll try again....

Crash happened:
I was adding plasma widgets to a second panel I have added, configured to autohide. I can add an Application Menu (kicker..), but when I try to add a Quicklauncher, plasma bombed out and reloaded. 

Backtrace:

Application: Plasma Workspace (plasma), signal SIGFPE
[Current thread is 0 (LWP 7013)]

Thread 3 (Thread 0xa958eb90 (LWP 7014)):
#0  0xb80bc430 in __kernel_vsyscall ()
#1  0xb695b075 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0
#2  0xb69c0b6e in QWaitCondition::wait () from /opt/project-neon/lib/libQtCore.so.4
#3  0xb7b37802 in ?? () from /opt/project-neon/lib/libQtNetwork.so.4
#4  0xb69bff90 in ?? () from /opt/project-neon/lib/libQtCore.so.4
#5  0xb695750f in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#6  0xb67af7ee in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 2 (Thread 0xa8cc7b90 (LWP 7016)):
#0  0xb80bc430 in __kernel_vsyscall ()
#1  0xb695b075 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0
#2  0xb69c0b6e in QWaitCondition::wait () from /opt/project-neon/lib/libQtCore.so.4
#3  0xa964f1f0 in RenderThread::run (this=0x8b5a9e4) at /build/buildd/kde-nightly-kdebase-20081128.7+svn890339/workspace/plasma/wallpapers/image/renderthread.cpp:90
#4  0xb69bff90 in ?? () from /opt/project-neon/lib/libQtCore.so.4
#5  0xb695750f in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#6  0xb67af7ee in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 1 (Thread 0xb4ba86e0 (LWP 7013)):
[KCrash Handler]
#6  0xa8460cb7 in QuicklaunchApplet::refactorUi (this=0x9258270) at /build/buildd/kde-nightly-kdebase-20081128.7+svn890339/workspace/plasma/applets/quicklaunch/quicklaunchApplet.cpp:171
#7  0xa8461ccb in QuicklaunchApplet::constraintsEvent (this=0x9258270, constraints={i = -1075071220})
    at /build/buildd/kde-nightly-kdebase-20081128.7+svn890339/workspace/plasma/applets/quicklaunch/quicklaunchApplet.cpp:152
#8  0xb7f32a40 in Plasma::Applet::flushPendingConstraintsEvents (this=0x9258270) at /build/buildd/kde-nightly-kdelibs-20081128.7+svn890338/plasma/applet.cpp:958
#9  0xb7f3343f in Plasma::Applet::timerEvent (this=0x9258270, event=0xbfebbc8c) at /build/buildd/kde-nightly-kdelibs-20081128.7+svn890338/plasma/applet.cpp:1676
#10 0xb6abaebf in QObject::event () from /opt/project-neon/lib/libQtCore.so.4
#11 0xb72c14ef in QGraphicsWidget::event () from /opt/project-neon/lib/libQtGui.so.4
#12 0xb6d1e6fc in QApplicationPrivate::notify_helper () from /opt/project-neon/lib/libQtGui.so.4
#13 0xb6d25aaf in QApplication::notify () from /opt/project-neon/lib/libQtGui.so.4
#14 0xb792ec03 in KApplication::notify (this=0x88f3648, receiver=0x9258270, event=0xbfebbc8c) at /build/buildd/kde-nightly-kdelibs-20081128.7+svn890338/kdeui/kernel/kapplication.cpp:307
#15 0xb6aab591 in QCoreApplication::notifyInternal () from /opt/project-neon/lib/libQtCore.so.4
#16 0xb6ad7ce7 in ?? () from /opt/project-neon/lib/libQtCore.so.4
#17 0xb6ad4f50 in ?? () from /opt/project-neon/lib/libQtCore.so.4
#18 0xb5c5c6f8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#19 0xb5c5fda3 in ?? () from /usr/lib/libglib-2.0.so.0
#20 0xb5c5ff61 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#21 0xb6ad4ea8 in QEventDispatcherGlib::processEvents () from /opt/project-neon/lib/libQtCore.so.4
#22 0xb6db22e5 in ?? () from /opt/project-neon/lib/libQtGui.so.4
#23 0xb6aa9f9a in QEventLoop::processEvents () from /opt/project-neon/lib/libQtCore.so.4
#24 0xb6aaa15a in QEventLoop::exec () from /opt/project-neon/lib/libQtCore.so.4
#25 0xb6aaf1fd in QCoreApplication::exec () from /opt/project-neon/lib/libQtCore.so.4
#26 0xb6d1e427 in QApplication::exec () from /opt/project-neon/lib/libQtGui.so.4
#27 0xb8067736 in kdemain (argc=1, argv=0xbfebc094) at /build/buildd/kde-nightly-kdebase-20081128.7+svn890339/workspace/plasma/shells/desktop/main.cpp:58
#28 0x08048762 in main (argc=85, argv=0x0) at /build/buildd/kde-nightly-kdebase-20081128.7+svn890339/obj-i486-linux-gnu/workspace/plasma/shells/desktop/plasma_qgv_dummy.cpp:3

i cant install -dbg packages for the libqtcore & libqtgui.... but for libglib
 i can if you want....

for the empty menus, i was given a quick fix on IRC.

open a console as normal user and run the following commands:
1) cp /etc/xdg/menus/kde4-applications.menu ~/.config/menus/applications.menu
2) kbuildsycoca

all is good :)

the crash bug was fixed in svn since as well.. huzzuh.