I've been having the same problem with Samsung's update server for quite a while, as have others. There doesn't seem to be any way to download the updates from a web site to your computer either.
I follow this sequence to update the software for my new LED TV:
- Software Upgrade
- By Online
- ERROR MESSAGE reads, "Connection Failed. (600)"
I know the Ethernet cable connection to the internet is working correctly because I can get current Weather, Stocks, etc. on the Internet display on the TV screen.