[Qgis-user] QGIS core dump at startup

[GFZ Hydrologie]

on kubuntu 14.04 LTS (running in Virtual Box on Windows 7) QGIS 2.8.1
launch aborts with core dumped.

So far I
purged qgis, removed all qgis plugins
re installed using repository
http://ppa.launchpad.net/ubuntugis/ubuntugis-unstable/ubuntu/

but without any success

on another machine with similar OS and QGIS there are no such problems.

any ideas?
cheers
kai

Warning: loading of qgis translation failed
[/usr/share/qgis/i18n//qgis_en_US]
Warning: loading of qt translation failed
[/usr/share/qt4/translations/qt_en_US]
Warning: Bus::open: Can not get ibus-daemon's address.
IBusInputContext::createInputContext: no connection to ibus-daemon
Warning: QGraphicsScene::addItem: item has already been added to this scene
Fatal: ASSERT failure in QList<T>::operator[]: "index out of range", file
/usr/include/qt4/QtCore/qlist.h, line 477
Stacktrace (piped through c++filt):
/usr/bin/qgis.bin[0x509ba0]
/usr/bin/qgis.bin(myMessageOutput(QtMsgType, char const*)+0x38)[0x509ca8]
/usr/lib/x86_64-linux-gnu/libQtCore.so.4(qt_message_output(QtMsgType, char
const*)+0x21)[0x7f6e8d568bb1]
/usr/lib/x86_64-linux-gnu/libQtCore.so.4(+0x70ff9)[0x7f6e8d568ff9]
/usr/lib/x86_64-linux-gnu/libQtCore.so.4(qFatal(char const*,
...)+0x94)[0x7f6e8d569804]
/usr/lib/libqgis_gui.so.2.8.1(QgsScaleComboBox::updateScales(QStringList
const&)+0x127)[0x7f6e8e1ecae7]
/usr/lib/libqgis_gui.so.2.8.1(QgsScaleComboBox::QgsScaleComboBox(QWidget*)+0x54)[0x7f6e8e1ed054]
/usr/bin/qgis.bin(QgisApp::createStatusBar()+0xa30)[0x519140]
/usr/bin/qgis.bin(QgisApp::QgisApp(QSplashScreen*, bool, QWidget*,
QFlags<Qt::WindowType>)+0xbb9)[0x54e9b9]
/usr/bin/qgis.bin(main+0x132b)[0x50421b]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf5)[0x7f6e8a4c5ec5]
/usr/bin/qgis.bin[0x5095e8]
Aborted (core dumped)
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