I'm having the same problem, I only just bought my TV yesterday so was panicking I had a shoddy model. I was able to update to the latest firmware this morning, though pretty much as soon as it updated I can't use any apps or check for new software updates. I should note, that on the Network tab it says 'connected to the internet' which is false, as I get Network Error(4) for everything.
Have called support, they're over-run and claim will call me back. Hopefully this gets resolved soon, as I was so excited to start using my new TV
Please let me know if you guys hear anything.