OpenGL & Qt

Hi everybody,
I’ve got some issue using Qt: I’ve install the lib and create a new Qt program in codeBlocks with contain only the basis:

#include <QApplication>
#include <QFont>
#include <QPushButton>

int main(int argc, char* argv])
    QApplication app(argc, argv);

    QPushButton quit("Quit");

    quit.resize(75, 30);
    quit.setFont(QFont("Times", 18, QFont::Bold));

    QObject::connect(&quit, SIGNAL(clicked()), &app, SLOT(quit()));;

    return app.exec();

Each time I launch this I’ve got a windows saying “Failed to find a suitable pixel format for the window – cannot create OpenGL context”. I installed the driver for my NVidia card and I’ve got a good result when I’m using glxgears.

Any idea ?