Is the computer you're trying to setup the Slingbox on also connected via Ethernet or Wi-Fi? If it is on Wi-Fi, I would hook it up the the same router with an Ethernet cable and try the setup again to see if you get the same errors. If you're already on Ethernet, I would also suggest checking your anti-virus to see if this may be blocking the unit for some reason.
I would also say to try another browser, especially if you're using Google Chrome as this has been causing a bit of trouble lately.
I hope this helps!!
I have tried to connect using Chrome and IE both direct into the router and using wi-fi with no luck.I haven't check the anti- virus however, I am using the same anti virus I have always had on this PC. I recently moved so router and internet provider have changed, so I knew I had to start fresh and reconfig the 350 from scratch. I just can't get the Slingbox to recognize anything in my new location. Willing to entertain any and all ideas. U-verse has even put in the MAC address for the Slingbox in my router and it still is not being located.