If: the cube is set to 192.168.1.254
and: The internet Gateway is set to 192.168.1.x
and: Your computer is set to 192.168.1.y
and: the computer and the cube are plugged into the same gateway

If you can not see the cube, perhaps the DNS setting are being reset from your defaults.
Set the Router to assign DNS, set the range to include your selection for ip addresses for the various devices
Set your computer to utilize the auto DNS settings, or put the specific information in place
Insure that your computer is not using an alternate IP as per "Alternate Configuration" tab.

After checking all of these thing 8 or 9 times, I would investigate the connective hardware, cables and hub connections.
Sometimes a new ethernet cable can save your day, even though the old one works in another machine just fine.