"Both installations"?
For what it's worth, I just tried to reproduce the installer crash on a fully updated Windows 7 SP1 64-bit Home Premium installation, installing MegaGlest to a separate NTFS partition at "F:\Game Files", but was unable to reproduce the crash. So I continue to guess something may have been wrong with your file system or your hardware.
This said, I'm glad to learn the game works for you now.