import QtMultimedia 5.0 fails on Windows

I try to run QtQuick2 example below in Qt5 Alpha on Windows7, but i got:

plugin cannot be loaded for module "QtMultimedia": Cannot load library C:/qt5/qtbase/imports/QtMultimedia/declarative_multimediad.dll: The specified module could not be found.
import QtMultimedia 5.0
^

import QtQuick 2.0
import QtMultimedia 5.0

Rectangle {
    width: 360
    height: 360
    Text {
        anchors.centerIn: parent
        text: "Hello World"
    }
}

Another plugins work fine such as QtSensor, QtLocation, QtQuick.Particles and etc.
Is there something obvious I've missed?