'renderText' produces error message "QGLShaderProgram: shader programs not supported" when used with 'renderPixmap'.

I don't use any shader program in my project. When I call
'QPixmap QGLWidget::renderPixmap ( int w = 0, int h = 0, bool useContext = false )'
with a call of
'void QGLWidget::renderText ( double x, double y, double z, const QString & str, const QFont & font = QFont(), int listBase = 2000 )'
in
'void QGLWidget::paintGL () '
a popup warning appears: "QGLShaderProgram: shader programs not supported". After that the program crashes. On older Qt Versions the same thing worked fine.