I certainly hope that after posting this on August 24th you are not still without answer. I am running into the same problem.
I connect the slingbox DIRECTLY to my router where my desktop is located.
Start the updating process. It slowly crawls to about 75% then shoots to 100% and attempts to restart the Slingbox.
At this point there is an Error Message stating it did not update correctly.
Multiple attempts will reveal no connection between Slingbox and the Router EVEN THOUGH IT IS DIRECTLY PLUGGED INTO IT!
I reset the Slingbox.
It brings up my Slingbox as "Unconfigured"
It goes through the motions of trying to update the Slingbox when the same Error appears again and again.
I have read your support forums and found them to be useless. Also, why can I not speak to someone on the phone on this matter?
What I understand from your post, is that you can't complete the Slingbox software update.
In this case, what I would recommend to you, is to connect the computer directly to the router using an Ethernet cord, just for the update and first Setup, after that you can connect using the wireless network.
Besides that, discard any streaming restriction or firewall preventing the Slingbox to connect properly, also, you can try to connect and Set the Slingbox up using a different computer to discard the current one as a potential issue.
You can contact the Technical Support using the following link's information, they will be able to check your Slingbox warranty status and provide the Support options based on that.