Is there a router in the mix? If yes, check that it has UPnP enabled. This is what allows your laptop to see the TV...
I have a Samsung ln52a750 TV with WiseLinkPro DLNA.
I'm network-connected to the TV and did an "auto setup", which assigned an IP address in the range of my network.
I did a "network test" on the TV which passed with flying colors.
I can ping the TV from my laptop on the same network.
However, when I hit the "WiseLink" button on my remote (it says no storage device attached), the TV doesn't seem to see the PlayOn Server I have installed on my destop (which works fine with my Xbox 360. Also, the Samsung MediaShare PC (or whatever it's called) software I installed on my desktop doesn't show "WiselinkPro Server", it says "Mediashare Server" or something. It also doesn't show the IP address of my TV so I can "allow" it in the server.