I already wrote here. But the topic is already closed.
I checked. Does not work (((You can register on the forum yourself and see this. New registered member widget shows a lot of recent posts on the forum.
The second field (число элементов) should not be 1, it's the number of posts it should display on widget. Please set it 2 or more. Then go to Dashboard > Forums > Dashboard and click the [Delete All Caches] button.