Your Internet connection. Just a USB Wireless Modem?
Did you read this PDF on setting up your Samsung
for Media use? I don't see where it connects to the Internet, but it connects to a shared DLNA server. Only a few specific brands/models.
I especially would want to know what the settings and test windows show. If connected properly, it should show good test results and there should be numbers from your Mac in the settings fields.
My tought s are that 1, your Mac cannot run the Samsung software unless in PC mode, and 2, it will not connect to the Mac because network settings my not be sent to the TV, you will have to set them manually.
This will result in the error message you see. Cannot connect because it can't find the media server.
So, to resolve number 2, look at the network the Mac has setup to share and then go to the TV settings and set TCP to Manual setup and add in numbers exactly the same, but use the Mac address as the router and make the TV on last number different. ie; if Mac is setting itself to sharte 10.0.0.1, use that as the router and make the TV 10.0.0.2
To resolve number 1, you need a PC running the Samsung software, or one of the media servers mentioned in the PDF. You will not be able to do this on the Mac unless it is running Parallels or VMWare Fusion or running in Boot Camp and in any of them, Windows XP - SP2 or Vista.
Let me know if this helps clear it up.