Same for me, first window pops and says something about loading the installer then just disapears, the installer exe still running in the background but it seems to do nothing
I just emailed the release coordinator about this. I have nothing to do with the installer, but hopefully we can get to the bottom of this very quickly!
Please note that this is a large EXE installer and therefore there will be a delay before the installer window pops up. If it doesn't happen after a minute or two then please contact the support team.