Which Qt version did you install ? MSVC ? MinGW ?

I just tried the latest Qt 5.5 release an the Qt Creator that comes with this release. At least on Windows the QtQuick.Extras work out of the box. If you use an older Qt Creator the Extras are not part of Qt Creator and you have to build the qml2puppet as described above.

For your own components which use C++ you should always build the qml2puppet.

Thanks, kuzulis!
You are right.
I updated driver of my Nvidia card (however manually).
Problem has been fixed!