I'm an IT Director and ran into this issue tonight with one of my clients. I was able to get it to work, but like many of you I was very frustrated, I followed the directions exactly. I almost gave up on the issue and was going to wait for more information, but I went back to the "Get Quickbooks Updates" checked the "Update Now" tab and noticed it said Quick Fix updates needed to exit Quickbooks and restart to install updates. I did this a few times, going back to "Get Quickbooks Updates" and "Update Now" tab, clicking on the blue "Update Now" button until it finally stated "Nothing New to Download".

I hope this information helps others, I feel like the answers where incomplete.