I just started a thread on the solution - if you can open your launcher but it is not updating, your launcher needs updating. I just took updated files from my computer that updated the launcher and downloaded the patch fine over to my other PC that would not update the launcher. It was stuck on January launcher version and gave me the error when I hit Play to download the patch. Both of these pc's run win7, wired on same network - the only difference is the one that ran fine was a much later install and the one that didn't work started from Beta - I am wondering if I should install a new retail copy of ffxiv. That, as far as I can see, is the only difference.