Not able set QPixmap to a MDI area subwindow in release mode

I am not able set QPixmap to a MDI area subwindow in release mode. Quite surprisingly, the same code works fine when i build it in debug mode.

the code is,

QPixmap lModelView(lstrFullFileName);
this->add3DModelView(lModelView,lstrFileName);
-------------------------------------------------------------------
CHI3DModelView* CHIDocument::add3DModelView(const QPixmap& arPixmap, QString aFileName)
{
CHI3DModelView *pModelView = new CHI3DModelView(arPixmap,aFileName);
......

return pModelView;
}
------------------------------------------------------------------------
CHI3DModelView::CHI3DModelView(const QPixmap& arPixmap, QString aFileName)
{
m_strFileName = aFileName;
QLabel *pLabel = new QLabel(this);
if(true == arPixmap.isNull())
QMessageBox::information(this,"","Poda");
pLabel->setPixmap(arPixmap);
pLabel->resize(100,100);
QHBoxLayout *pLayout = new QHBoxLayout();
pLayout->addWidget(pLabel);
setLayout(pLayout);
setContentsMargins(0,0,0,0);

setWindowTitle(m_strFileName);
}
-------------------------------------------------------------------------------------------

Can anyone help?