Qt 4.5 Embedded - some widgets crash

Hi,
I'm facing a problem with some widgets on Qt 4.5 Embedded running on blackfin with ucLinux.

1. QComboBox is displayed, but atempt to click on it freezes all application. The code is simple - just QWidget (or QMainWindow) with
{

QComboBox *pcb = new QComboBox(this);

pcb->addItem("1");
pcb->addItem("2");
pcb->addItem("3");
pcb->move(10,10);

}

2. QRadioButton is not displayed at all - actually whole application freezes at startup and nothing is displayed. When QRadioButton is replaced with QPushButton it's working.

Has anybody worked with QT4.5 for Embedded? Has anybody faced the same?
Regards,
Nikolay