QApplication compiles with gcc 4.7 but crashes

Question

from here http://nuwen.net/mingw.html I've downloaded gcc 4.7 and I've set this up in qt. Everything compiles fine in qt, unfortunately when I run my app (from qt) it crashes.
Any thougts?
Edit (this is this application, OS Win7, Qt 4.8):

#include <QApplication>
#include <QDialog>
int main(int c, char** v)
{
    QApplication app(c,v);
    QDialog* d = new QDialog();
    d->show();
    return app.exec();
}

Answer 1

If you update the compiler, you should probably recompile Qt.

Different version of gcc can work together, but they might be themselves compiled with incompatible options.