Version:           1.5.6 (Using KDE 3.5.5-0.2fc5 Fedora-Core) (using KDE KDE 3.5.5)
Installed from:    Fedora RPMs
Compiler:          gnat GPS 3.1.3 
OS:                Linux

On two separate computers (mine and a coworkers) Umbrello crashes when the following is attempted:
1)  Choose new Diagram - New - State Diagram - OK
2)  Add any state such as a start state
3)  Add another state
4)  Try to associate with a state transition arrow
5)  CRASH.

Backtrace:

(no debugging symbols found)
Using host libthread_db library "/lib/libthread_db.so.1".
(no debugging symbols found)
`shared object read from target memory' has disappeared; keeping its symbols.
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
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(no debugging symbols found)
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(no debugging symbols found)
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(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
[Thread debugging using libthread_db enabled]
[New Thread -1208396080 (LWP 3986)]
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
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(no debugging symbols found)
(no debugging symbols found)
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(no debugging symbols found)
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(no debugging symbols found)
(no debugging symbols found)
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(no debugging symbols found)
(no debugging symbols found)
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(no debugging symbols found)
[KCrash handler]
#6  0x081d00a9 in UMLObject::setUMLPackage ()
#7  0x08194b42 in ToolBarStateAssociation::addAssociationInViewAndDoc ()
#8  0x08194d97 in ToolBarStateAssociation::setSecondWidget ()
#9  0x081936c4 in ToolBarState::mouseRelease ()
#10 0x4e1b6401 in QScrollView::viewportMouseReleaseEvent ()
   from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#11 0x4e1b400f in QScrollView::eventFilter ()
   from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#12 0x4e086aec in QObject::activate_filters ()
   from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#13 0x4e086b6b in QObject::event () from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#14 0x4e0c43ac in QWidget::event () from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#15 0x4e01e92b in QApplication::internalNotify ()
   from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#16 0x4e01ff57 in QApplication::notify ()
   from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#17 0x4dc03723 in KApplication::notify () from /usr/lib/libkdecore.so.4
#18 0x4dfb61a8 in QETWidget::translateMouseEvent ()
   from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#19 0x4dfb4c9f in QApplication::x11ProcessEvent ()
   from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#20 0x4dfc6a6b in QEventLoop::processEvents ()
   from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#21 0x4e037dd0 in QEventLoop::enterLoop ()
   from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#22 0x4e037c96 in QEventLoop::exec () from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#23 0x4e01e43f in QApplication::exec () from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#24 0x08169cac in main ()

As a footnote, we are trying to use Umbrello on a research project where we must generate Ada95 and C++ code from UML.  We have many years experience in doing this with Rose and Software Thru Pictures.  Hopefully we'll have success with Umbrello.