I have my WD live connected via ethernet to my router and my Mac is wireless. works perfectly when i goto Network on my MAC. You may want to check your router settings and maybe set the WD into the DMZ list
Putting a device in (most) router’s DMZ list makes it freely accessible with no restrictions from the internet.
And doesn’t make much sense anyways. Why would you want your HUB on a different subnet than your home computer? (Yes, I am sure there are some folks here with complex setups and multiple subnets that might do that, but not for most home users…)
If you search the board, there are a lot of good posts on troubleshooting connection issues, some specific to Macs.