I've downloaded the latest setup program 3.6.8 again and just tried to extract the 64bit msi using a window 7 Pro SP1 32bit laptop and now get the same side-by-side error on Win 7 32bit which worked before. I even tried 3.6.5 which fails with the same error. Microsoft must of changed something in one of the security updates. It can't be the virus checker because they aren't run on the internal servers which also fail. I can't think of any common thing that links all the units I have tried together making every one fail, each downloading their own version of the setup program.
EDIT
Just tried XP Pro and get This application has failed to start because the application configuration is incorrect.
I'm at a loss why only I can't run it when it is obvious that others can.