Comment 1 for bug 1096105

Can you try re-downloading the installer from https://one.ubuntu.com/windows/ubuntuone-4.0.0-windows-installer.exe

It seems like the download may have been corrupted. I'm able to install 4.0.0 on several OSes and no one else has reported this same error, so it feels unlikely that it's a problem in the codebase.