qt/3d plugins loading failed on N900

I compile qt/3d for maemo5 in scratchbox and cp relevant libs to N900.some demos and examples work fine on N900.But it will crash when you load model file,such as *.bez *.obj ,no matter resource file or native file.I suppose QGLAbstractScene::loadScene results in this error.and I qDebug and find that QGLAbstractScene::supportformats() always return an empty QStringlist.(no model file formats supported?)
Btw I've already cp the related files(libqsceneai.so libqscenebezier.so)to /usr/lib/qt4/plugins/sceneformats and qt3d-qtquick plugins(libqthreedqmlplugin.so qmldir shapes) to /usr/lib/qt4/import/Qt3D/.
meanwhile,I manually set QT_PLUGIN_PATH to /usr/lib/qt4/plugins,But still didn't work out.