I have a WD Live hub, and just bought the Live plus for my bedroom. I am connecting via network to my Live Hub.
The live plus does not display thumbnails for all my videos. Just random ones. The thumbnails were all created by the hub. So for each video, there is a corresponding .xml and .jpg. All three files are the same name with the appropriate extentions.
The thumbs display fine on the hub, just not on the live plus.