1. new drawing
2. tools -> circle
3. click center -> crash

source code segment:

void RGraphicsSceneQt::exportArcSegment(const RArc& arc) {
    RPainterPath& path = draftMode ? currentPainterPathDraft : currentPainterPath;

    // try QPainterPath arcTo method first but this can be very
    // inaccurate (+/- 0.01 difference from start- / end point):
    RPainterPath p;
    RBox box(arc.center - RVector(arc.radius, arc.radius), arc.center
            + RVector(arc.radius, arc.radius));
    p.moveTo(arc.getStartPoint());
    p.arcTo(box.toQRectF(), 360 - RMath::rad2deg(
            arc.startAngle), -RMath::rad2deg(arc.getSweep()));
=>  QPainterPath::Element e1 = p.elementAt(1);
    double errorStart = RVector(e1.x, e1.y).getDistanceTo(arc.getStartPoint());
    QPointF ep = p.pointAtPercent(1.0);
    double errorEnd = RVector(ep.x(), ep.y()).getDistanceTo(arc.getEndPoint());

    if (errorStart<1.0e-5 && errorEnd<1.0e-5) {
        // TODO: check if this is ever reached:
        path.addPath(p);
        return;
    }

stack trace:

Thread [1] 6814 (Suspended : Signal : SIGABRT:Aborted)	
	__kernel_vsyscall() at 0xffffe424	
	raise() at 0xb4efc8df	
	abort() at 0xb4efe220	
	RMainWindow::messageHandler() at RMainWindow.cpp:63 0x8ee4076	
	qt_message_output() at 0xb5356f65	
	0xb53571ab	
	qFatal() at 0xb53572c9	
	qt_assert() at 0xb5357355	
	QPainterPath::elementAt() at qpainterpath.h:400 0x8a8163e	
	RGraphicsSceneQt::exportArcSegment() at RGraphicsSceneQt.cpp:210 0x8dc5c5d	
	RExporter::exportArc() at RExporter.cpp:831 0x8ec82c7	
	RGraphicsSceneQt::exportArc() at RGraphicsSceneQt.cpp:125 0x8dc570f	
	RExporter::exportCircle() at RExporter.cpp:911 0x8ec899e	
	RCircleEntity::exportEntity() at RCircleEntity.cpp:110 0x8de6a2a	
	RExporter::exportCurrentEntity() at RExporter.cpp:603 0x8ec7430	
	RGraphicsScene::exportCurrentEntity() at RGraphicsScene.cpp:244 0x8ecff0b	
	RExporter::exportEntity() at RExporter.cpp:557 0x8ec7220	
	RDocumentInterface::previewOperation() at RDocumentInterface.cpp:1,882 0x8ebc561	
	REcmaDocumentInterface::previewOperation() at REcmaDocumentInterface.cpp:5,247 0x88ce888	
	0xb6bd813c	
	0xb6ac1f68	
	0xb6a9164c	
	0xa7fd43b8	
	0xb6a423e3	
	0xb6af06e0	
	0xb6ac201e	
	QScriptValue::call() at 0xb6bd2e67	
	REcmaShellActionAdapter::coordinateEventPreview() at REcmaShellActionAdapter.cpp:1,341 0x8c306d6	
	RDocumentInterface::previewClickEvent() at RDocumentInterface.cpp:770 0x8eb996a	
	RDocumentInterface::mouseMoveEvent() at RDocumentInterface.cpp:621 0x8eb91b7	
	RGraphicsScene::handleMouseMoveEvent() at RGraphicsScene.cpp:152 0x8ecfbd1	
	RGraphicsView::handleMouseMoveEvent() at RGraphicsView.cpp:427 0x8ed23aa	
	RGraphicsViewQt::mouseMoveEvent() at RGraphicsViewQt.cpp:191 0x8dd213b	
	QWidget::event() at 0xb58da661	
	RGraphicsViewQt::event() at RGraphicsViewQt.cpp:102 0x8dd1fb8	
	QApplicationPrivate::notify_helper() at 0xb5871d7c	
	QApplication::notify() at 0xb58772c4	
	QCoreApplication::notifyInternal() at 0xb547215b	
	QApplicationPrivate::sendMouseEvent() at 0xb5875152	
	0xb59066b5	
	QApplication::x11ProcessEvent() at 0xb5905d26	
	0xb5932f04	
	g_main_context_dispatch() at 0xb4af3509	
	0xb4af3d10	
	g_main_context_iteration() at 0xb4af3fce	
	QEventDispatcherGlib::processEvents() at 0xb54a2741	
	0xb5932a55	
	QEventLoop::processEvents() at 0xb547131d	
	QEventLoop::exec() at 0xb54715aa	
	QCoreApplication::exec() at 0xb5473701	
	qtscript_QCoreApplication_static_call() at 0xb0a9c4b7	
	0xb6bd813c	
	0xb6ac1f68	
	0xb6a9164c	
	0xb09fe9e9	
	0xb6a44262	
	0xb6a445f7	
	0xb6bb0f92	
	QScriptEngine::evaluate() at 0xb6bba46f	
	RScriptHandlerEcma::eval() at RScriptHandlerEcma.cpp:728 0x8787984	
	RScriptHandlerEcma::doScript() at RScriptHandlerEcma.cpp:724 0x8787868	
	RScriptHandler::init() at RScriptHandler.cpp:31 0x8f0163a	
	main() at main.cpp:172 0x87815fb