Problem with closing the application

[macbeth]

Hello, I have a very odd problem.
During the start-up of my application, I do some checks to see whether the plugins were loaded properly, etc. All these checks happen in the constructor of the MainWindow (descendant of QMainWindow) and when some of them fails, I want to close the application. However, using QApplication::close(), close(), qApp->quit() or destroy() has no effect (or, at least it does not close the application, I am not aware of any other side-effects), the MainWindow shows up (and later my application crashes because it assumes the plugins are already loaded).

My closeEvent() is reimplemented,

void MainWindow::closeEvent(QCloseEvent *event){
	workspace->closeAllWindows();
	if (activeWindow()) {
		event->ignore();
	} else {
		event->accept();
	}
}

void MainWindow::closeEvent(QCloseEvent *event){
	workspace->closeAllWindows();
	if (activeWindow()) {
		event->ignore();
	} else {
		event->accept();
	}
}

To copy to clipboard, switch view to plain text mode 

but I think that the problem is elswhere, because I checked that the event->accept() line is called.

Do you have any ideas how to close the application?

Thanks...