XPropertySet reference is null

Hello, Colleagues !

I try to parse odt-document as same as example DocumentLoader

But when I try to obtain

    _xComponentContext = Reference< XComponentContext >( ::cppu::bootstrap() );
   _xMultiComponentFactoryClient = Reference< XMultiComponentFactory >( _xComponentContext->getServiceManager() );
_xInterface = Reference< XInterface >(
                 _xComponentContext )
_resolver = Reference< XUnoUrlResolver >( _xInterface, UNO_QUERY );
// gets the server component context as property of the office component factory
_xPropSet = Reference< XPropertySet >( _xInterface, UNO_QUERY );

_xPropSet became null, and I cannot get any context. Which way I can take content of test document ?