Version:            (using KDE 4.3.1)
Installed from:    Gentoo Packages

Hello, I had crash with the owygen style:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fc8dac8e740 (LWP 2193)]
0x00007fc8da147844 in QWidget::style (this=0xe84400) at kernel/qwidget.cpp:2294
2294    kernel/qwidget.cpp: No such file or directory.
        in kernel/qwidget.cpp
(gdb) bt
#0  0x00007fc8da147844 in QWidget::style (this=0xe84400) at kernel/qwidget.cpp:2294
#1  0x00007fc8da3c5b9a in updateWidgets (widgets=@0x7fff6bed68d0) at styles/qstylesheetstyle.cpp:2738
#2  0x00007fc8da3c5e2d in QStyleSheetStyle::repolish (this=<value optimized out>, app=<value optimized out>) at styles/qstylesheetstyle.cpp:2944
#3  0x0000000000458b2d in loadStyle () at main.cpp:209
#4  0x0000000000410ea6 in optionsDialog::apply (this=0xc7b960) at Options.cpp:276
#5  0x00000000004a62b0 in optionsDialog::qt_metacall (this=0xc7b960, _c=QMetaObject::InvokeMetaMethod, _id=2, _a=0x7fff6bed73b0) at moc_Options.cpp:83
#6  0x00007fc8d80bc880 in QMetaObject::activate (sender=0x13b6a80, from_signal_index=<value optimized out>, to_signal_index=30, argv=0x0) at kernel/qobject.cpp:3101
#7  0x00007fc8da6f25f7 in QAbstractButton::clicked (this=0xe84400, _t1=false) at .moc/release-shared/moc_qabstractbutton.cpp:200
#8  0x00007fc8da45baf0 in QAbstractButtonPrivate::emitClicked (this=0xcb0ad0) at widgets/qabstractbutton.cpp:543
#9  0x00007fc8da45ca02 in QAbstractButtonPrivate::click (this=0xcb0ad0) at widgets/qabstractbutton.cpp:536
#10 0x00007fc8da45cc25 in QAbstractButton::mouseReleaseEvent (this=0x13b6a80, e=0x7fff6bed7d00) at widgets/qabstractbutton.cpp:1115
#11 0x00007fc8da1577c8 in QWidget::event (this=0x13b6a80, event=0x7fff6bed7d00) at kernel/qwidget.cpp:7549
#12 0x00007fc8da1028dd in QApplicationPrivate::notify_helper (this=0x8cb980, receiver=0x13b6a80, e=0x7fff6bed7d00) at kernel/qapplication.cpp:4056
#13 0x00007fc8da10bc81 in QApplication::notify (this=<value optimized out>, receiver=0x13b6a80, e=0x7fff6bed7d00) at kernel/qapplication.cpp:3758
#14 0x00007fc8d80a922b in QCoreApplication::notifyInternal (this=0x8cb960, receiver=0x13b6a80, event=0x7fff6bed7d00) at kernel/qcoreapplication.cpp:606
#15 0x00007fc8da10af71 in QApplicationPrivate::sendMouseEvent (receiver=0x13b6a80, event=0x7fff6bed7d00, alienWidget=0x13b6a80, nativeWidget=0xc7b960, buttonDown=<value optimized out>, lastMouseReceiver=@0x7fc8daaa6f70)
    at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:216
#16 0x00007fc8da16e12c in QETWidget::translateMouseEvent (this=0xc7b960, event=<value optimized out>) at kernel/qapplication_x11.cpp:4404
#17 0x00007fc8da16cc25 in QApplication::x11ProcessEvent (this=0x8cb960, event=0x7fff6bed96f0) at kernel/qapplication_x11.cpp:3545
#18 0x00007fc8da19356c in x11EventSourceDispatch (s=0x8d0620, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#19 0x00007fc8d7696dd0 in IA__g_main_context_dispatch (context=0x8cf440) at gmain.c:1824
#20 0x00007fc8d769a6a8 in g_main_context_iterate (context=0x8cf440, block=1, dispatch=1, self=<value optimized out>) at gmain.c:2455
#21 0x00007fc8d769a85e in IA__g_main_context_iteration (context=0x8cf440, may_block=1) at gmain.c:2518
#22 0x00007fc8d80d12cf in QEventDispatcherGlib::processEvents (this=0x8ccae0, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:327
#23 0x00007fc8da192ce8 in QGuiEventDispatcherGlib::processEvents (this=0xe84400, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#24 0x00007fc8d80a7832 in QEventLoop::processEvents (this=<value optimized out>, flags={i = 1810733536}) at kernel/qeventloop.cpp:149
#25 0x00007fc8d80a7a1c in QEventLoop::exec (this=0x7fff6bed9a20, flags={i = 1810733616}) at kernel/qeventloop.cpp:197
#26 0x00007fc8d80a9e5c in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#27 0x000000000045eb08 in main (argc=1, argv=0x7fff6bedaa98) at main.cpp:920

And at my code is:
QApplication::setStyleSheet("new style: QTreeWidget {
background-image        : url(/home/user/Desktop/Desktop3/ultracopier-general/ultracopier/src/styles/Oxygen/extra/background-playlist.png);
background-position     : center;
background-repeat       : no-repeat;
background-color        : #fff;
background-attachment   : fixed;
}");