designer plugin fails to load

I'm running qwt-5.0.2, qt-4.3.3, mingw
I compiled QWT with enabled option QwtDesigner

Now the Designer says that qwt plugin is not a valid one.

Did you compile a release version of Qwt?

yes, both QT and QWT are compiled in release mode only.
qwt examples work correctly.

Strange. I'm having this problems on win vista x64.
On XP i got no problems.. :eek:

I compiled qwt_designer_plugin.dll under win XP and copied it into my Vista x64. The plugin is now working.
Dont know how to debug this problem. Maybe the problem is in x64 or maybe in Vista

Now i'm shure that was not the problem of QWT. I was getting this problem when i was using a precompiled version of QT ( qt+mingw downloaded from trolltech ).

So this time I downloaded a QT source package and compiled it with mingw myself. Then i compiled the qwt. The plugin loads without any problems.

qt_4.3.3 qwt_5.0.2 mingw_3.81 vista_x64

Hi
My designer will not loaded either. I was wondering if it was the dependencies on the Qt dll or on ms crt dll.

qt_4.3.3 qwt_5.0.2 Visual Studio 2005