Media Player cannot browse network via homeplugs but can if...

Hello everyone.

I have a Network Media Tank A-110 Media Player (NMT) which I love, but I have never been able to browse my WORKGROUP through my homeplug home network. Instead I have had to use iHome server installed on my PC (connected to a homeplug) and a standard UPnP server on my NAS (also connected to a homeplug) in order for my NMT to see my media files. My NMT is connected to a Netgear gigabyte ethernet switch (as is my blu ray, AV AMP, TV) which itself is plugged into a 200gb Homeplug.

However today I decided to plug my PC directly into the gigabyte ethernet switch using a 10m cat5 cable, and lo & behold - my NMT can now browse my entire network!

Of course I wanted to check that it wasn't a fluke so I unplugged it and plugged my pc back into the homeplug, and the NMT cannot now see the WORKGROUP to browse at all.

It seems that, somehow, the homeplugs are stopping my NMT from browsing the network.

Anyone have any ideas why this should be??

To be clear I have no problems accessing the internet via my NMT OR the servers on my PC and NAS. However I want to browse WORKGROUP as it facilitates easiest use of media shares.