I've tried your demo on Linux/X11 with Qwt 5.1/Qt 4.4.2 without problems.
But your demo code does not much, so you can expect, that the reason for it is Qt downwards and Windows specific.
I recommend to upgrade to Qt 4.4.3 build it in debug mode and rerun your demo under gdb control. And again: try to learn/understand your debugger - whenever an applicaton crashes you can see it in your debugger.
Uwe
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