WDTV Live freezing problems

I had the previous version of the WDTV  live (without WIFI) and that had a lot of problems and stutter. I sold that and bought the new one with WIFI and still have problems whilst streaming wired or wireless, regardless of firmware. The wired connection is thru Home plugs. The wifi connection shows all the bars , full strength, but the picture freezes and audio goes away for several minutes and then comes bac. When I connect a USB pendrive or a higher capacity drive (500gb), to the front usb, playback is fine. Can someone advice how to overcome this problem. I would have continued to use the large drive connected to the USB, but my router and computer and the NAS are in another room and all my downloads are held on the NAS. All advice highly appreciated, thanks.

Strange thing to have the same problems when wired

how are the devices setup?

Switch, router, humplugs?

Please provide more info

The wired connection is through Homeplugs. I have two kinds one panasonic (Panasonic BL-PA100KT HD-PLC Ethernet Adapter) and the other Devolo (Dlan200). 

The NAS DS211j is conencted in a adjacent room directly to the router. I have placed a Access point in the living room where the WDTV live is located and at the moment am getting full bar wifi signal on all devices including the WDTV.