I have 3 WDTV Boxes 1 - WDTV Live Hub 1-WDTV Live 1- WDTV Live Hub Plus.
I am able to share and see the shares on the live hub on the other two live boxes, But I am not able to see the shares on the other two boxes.
The Live Hub can not see any computer on the network. yet the other two boxes see’s all the other computers.
I have tried every thing i can think of. Any idea’s
Live Hub and Live Hub Plus? Hmmm. 
Did you change the NAME on all boxes so they’re unique?
Sorry I meant to say WDTV Live Plus not live hub plus.
all three have unique names and the same workgroup name.
Try deleting and retyping the workgroup name in the hub again. This worked for me once when nothing was showing up in my network shares after a reboot.
I changed the workgroup to the name of the work group of my windows servers. and the servers showed up in the list of shares but none of the WDTV Live boxes did.
I was trying to have all the WDTV boxes on there own workgroup so they will only see each other.
My WDTVLIVEHUB simply appeared in Windows Explorer when I connected it then went into the SETTINGS for NETWORK and had it AUTO detect the network.
It worked for Ethernet (wired) and Wireless both. Wireless required a compatible USB adapter (there’s a list here somewhere) and I also had to type in my password as it was SECURED (you absolutely should use a secured wi-fi network).
You can see the WDTVLIVEHUB from your computer very easily. You only need the WORKGROUPS setup properly to view your computers FROM the WDTVLIVEHUB itself.
Did you ever find a solution? I am having a similar problem where none of the Live or Live+ devices will see each other and I can’t see them from PCs but they can access DLNA and Network Shares without any trouble.