Problem with adding many curves in qwtplot on Realtime

Hi... I'm working on an example of plotting on Real time and i have some problems, when i double click on the plot i can add one curve on the plot , but the problem is when i arrived on 5 curves and i want to add a new curve , the program crached.

Here is my method that is responsable of adding curves

Code:

void	CPlot:: mouseDoubleClickEvent(QMouseEvent *pEvent)
{
 
	if(pEvent->button() == Qt::LeftButton)
	{
		if(m_iNumbergraphe < MAX_GRAPHE_NUMBER)
		{
			QwtPlotCurve *curve;
			QVector<QPointF>*  values;
	                values=new QVector<QPointF>();
			curve = new QwtPlotCurve( "Entre "+QString::number(m_iNumbergraphe*(-2))+"et "+QString::number(m_iNumbergraphe*2) );
			curve->setPen( Qt::GlobalColor(20- m_iNumbergraphe) );
			curve->attach( this );
			m_graphe[m_iNumbergraphe].pBuffer = new CBufferCirculaire();
			m_graphe[m_iNumbergraphe].pStyle  = curve;
			m_graphe[m_iNumbergraphe].pPendingValues = values;
			cStat.initBuffers(m_graphe[m_iNumbergraphe].pBuffer,m_iNumbergraphe);
			showCurve( m_graphe[m_iNumbergraphe].pStyle, true );
			m_iNumbergraphe++;
		}
	}
}