No output on frame buffer (arm target board)

Hello to Every one,

I am trying to run qtopia hello world application on arm target board
but no output in lcd frame device.While It is successfully runnning on qvfb.

example is :
int main(int argc, char **argv)
{

printf("before app object creation\n");
QApplication a(argc, argv);
printf("after app object creation\n");
printf("before push button object creation\n");
QPushButton hello("Hello,World", 0);
printf("after push button object creation\n")
hello.resize(100,30);
hello.show();
return a.exec();

}
output :
before app object creation
after app object creation
before push button object creation
....
......
......

After that application gets hangs.

Thanks in advance

Best Regards,
Devendra