there is a warning at application output

Starting C:\debug\sdf.exe...
couldn't create image from  "" 

#include <QMainWindow>
#include <QGraphicsScene>
#include <QGraphicsTextItem>
#include <QGraphicsRectItem>
#include <QGraphicsSvgItem>

namespace Ui {
    class MainWindow;
}

class MainWindow : public QMainWindow {
    Q_OBJECT
public:
    MainWindow(QWidget *parent = 0);
    ~MainWindow();

protected:
    void changeEvent(QEvent *e);
		QGraphicsScene *scene;
		QGraphicsSvgItem *svg_item;

private:
    Ui::MainWindow *ui;

	private slots:
		void click123();
};

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <QGraphicsSvgItem>
#include <QGraphicsRectItem>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

		scene = new QGraphicsScene();

		ui->graphicsView->setScene(scene);

		connect(ui->pushButton, SIGNAL(clicked()), this, SLOT(click123()));

		svg_item = new QGraphicsSvgItem("C:/tux_camera.svg");
		svg_item->setPos(20, 20);

		scene->addItem(svg_item);

}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::changeEvent(QEvent *e)
{
    QMainWindow::changeEvent(e);
    switch (e->type()) {
    case QEvent::LanguageChange:
        ui->retranslateUi(this);
        break;
    default:
        break;
    }
}

void MainWindow::click123() {

	//ui->graphicsView->scale(4.0, 4.0);

}