Just bought a second hand DS101J and my setup is as follows:
Netgear DGN2200 --> Linksys WRT54gs --> DS101J
O/S = Windows 7 x64 throughout all devices.
I can connect and see all the files through windows explorer through my desktop which is a wired connection.
When i try to view the diskstation through the same process i.e. Start > Computer > Network - then it is not visible.
I have checked and seen that the same subnet is being used so this is not the issue.
Your help would be greatly appreciated.